Why Ulnar Nerve Pain Requires Specific Mouse Choices
Choosing the best mouse for ulnar nerve pain requires understanding why generic ergonomic mouse advice fails this specific condition. The ulnar nerve travels from your neck through the cubital tunnel at your inner elbow, down the ulnar (pinky) side of your forearm, and through Guyon's canal at the heel of your palm to your pinky and ring fingers. Compression anywhere along this path causes ulnar nerve symptoms.
Mouse use specifically aggravates ulnar nerve compression through three mechanisms. Ulnar deviation (wrist bending toward pinky) compresses Guyon's canal at the wrist. Hypothenar contact pressure (palm heel resting on hard surface) compresses Guyon's canal externally. Elbow flexion during prolonged mouse use compresses the cubital tunnel. The right mouse addresses all three mechanisms. Generic ergonomic mice may address one or none.
This comprehensive guide ranks 10 mice by ulnar nerve safety tier. Tier 1 vertical mice (safest) eliminate forearm pronation and reduce ulnar deviation through handshake position. Tier 2 sculpted mice with side scoops reduce hypothenar contact pressure. Tier 3 trackballs eliminate wrist movement entirely allowing stationary positioning that bypasses both ulnar deviation and hypothenar friction.
The Single Most Important Ulnar Nerve Insight
"Ulnar nerve compression happens at TWO sites: the elbow (cubital tunnel) AND the wrist (Guyon's canal). Your mouse choice affects BOTH." Most ergonomic mouse advice addresses wrist position only. Ulnar nerve sufferers need mice that reduce forearm pronation (decreasing wrist ulnar deviation at Guyon's canal) AND elbow flexion through proper desk positioning (decreasing cubital tunnel compression). Vertical mice address both simultaneously. Sculpted mice address only the wrist site.
Ulnar Nerve Anatomy: Cubital Tunnel and Guyon's Canal
Understanding ulnar nerve anatomy explains why mouse choice matters. The ulnar nerve has two primary compression sites that mouse use can aggravate. Knowing these sites helps you identify which mouse features address your specific symptoms. The anatomy below shows the nerve path and both compression sites with mouse-related aggravators highlighted.
Ulnar Nerve Path and Compression Sites
The ulnar nerve travels from the C8-T1 spinal nerves through your neck, behind your inner elbow (cubital tunnel), down the ulnar forearm, and through Guyon's canal at the heel of your palm to innervate your pinky and ring fingers plus several intrinsic hand muscles.
Notice the two compression sites: cubital tunnel at the inner elbow (Site 1) and Guyon's canal at the wrist heel (Site 2). Mouse use aggravates both sites through different mechanisms. Right mouse choice addresses both simultaneously. Wrong mouse choice can compound compression at one or both sites.
Ulnar Nerve vs Carpal Tunnel vs Radial Nerve
Confusion exists between ulnar nerve pain, carpal tunnel syndrome (median nerve), and radial nerve compression. Each affects different fingers and requires different mouse interventions. The distinction below helps identify whether you have ulnar nerve pain specifically or one of the related nerve conditions. Choosing the wrong mouse for the wrong condition delays recovery.
Ulnar Nerve (This Guide)
Compression at cubital tunnel (elbow) or Guyon's canal (wrist). Affects pinky and ring fingers.
Inner forearm pathwayMedian Nerve (CTS)
Compression at carpal tunnel (wrist). Affects thumb, index, middle, half of ring finger.
Center palm pathwayRadial Nerve
Compression at upper arm or wrist. Affects thumb, index, and back of hand.
Outer forearm pathwayQuick identification: If your pinky and ring finger tingle or go numb, you likely have ulnar nerve compression. If your thumb, index, and middle finger tingle, you likely have carpal tunnel syndrome (median nerve). See our CTS mouse hub for carpal tunnel-specific picks. If the affected fingers don't match either, consult a physician for diagnosis.
Three Mouse Aggravators of Ulnar Nerve Pain
Mouse use aggravates ulnar nerve pain through three specific mechanisms. Understanding each mechanism helps identify which mouse features matter most for your specific symptoms. The right mouse for ulnar nerve pain addresses all three mechanisms. Generic ergonomic mice typically address only one mechanism leaving others unmitigated.
Ulnar Deviation
Wrist bending toward pinky side compresses Guyon's canal at the wrist. Vertical mice eliminate this.
Hypothenar Pressure
Palm heel resting on hard surface externally compresses Guyon's canal. Side scoops on mice reduce this.
Elbow Flexion
Prolonged bent elbow compresses cubital tunnel at the inner elbow. Desk position matters as much as mouse.
Research validation: Vertical mouse designs measurably reduce forearm pronation and ulnar deviation according to Human Factors 2008 research on mouse posture. A 2015 Applied Ergonomics review confirmed alternative mice (vertical and trackball) can reduce pronation and some muscle activity, with effects varying by design and setup. (Influence of computer mouse design on hand and forearm posture, Human Factors 2008. Alternative computer mouse designs and upper-limb posture, Applied Ergonomics 2015.)
3-Tier Ulnar Nerve Safety Framework
Not all "ergonomic" mice are safe for ulnar nerve pain. The 3-tier safety framework below organizes mouse types by their ulnar nerve-specific impact. Tier 1 mice address all three ulnar aggravators (deviation, hypothenar pressure, pronation). Tier 2 mice partially address them. Tier 3 mice eliminate wrist movement entirely through stationary trackball position.
Ulnar Nerve Safety Tier Framework
Use this framework when evaluating any mouse for ulnar nerve pain. The categories below directly affect cubital tunnel and Guyon's canal compression during daily mouse use.
TIER 1: Safest
Vertical handshake position. Eliminates pronation and ulnar deviation. Most ulnar users.
Picks 1-5 below
TIER 2: Moderate
Sculpted with side scoops. Reduces hypothenar contact pressure. Mild ulnar cases.
Picks 6-8 below
TIER 3: Stationary
Trackball stationary position. Eliminates wrist movement entirely. Severe cases.
Picks 9-10 below
6 Features That Define the Best Mouse for Ulnar Nerve Pain
The best mouse for ulnar nerve pain combines features that address all three aggravator mechanisms. Match your specific ulnar nerve symptoms to the features below when evaluating mice. Not every mouse delivers all six features. Prioritize vertical handshake position and side scoops as the two most critical features for genuine ulnar nerve relief.
Vertical Handshake Position
45-90° vertical angle eliminates forearm pronation and reduces ulnar deviation at wrist.
Side Scoops / Pinky Lip
Lifts hypothenar away from desk surface reducing external Guyon's canal compression.
Lightweight Design
Under 135g reduces grip force required. Lower muscle tension equals less nerve compression.
Wireless Connectivity
Bluetooth or 2.4GHz. Eliminates cable drag forcing compensating ulnar deviation.
Programmable Buttons
Reduce total click volume via macros. Fewer clicks mean less ulnar muscle activation.
Adjustable Angle
Some vertical mice offer adjustability. Fine-tune ulnar nerve pressure points to your anatomy.
All 10 Best Mouse for Ulnar Nerve Pain Picks Compared
Use the comparison table below to shortlist before reading the full reviews. Sort by ulnar safety tier, vertical angle, weight, or price tier. All 10 picks are evaluated specifically for ulnar nerve impact with explicit tier classification matching cubital tunnel and Guyon's canal protection levels for daily mouse use.
| # | Mouse | Ulnar Tier | Type | Vertical Angle | Weight | Price | Best For |
|---|---|---|---|---|---|---|---|
| 1 | Logitech MX Vertical | SAFEST | Vertical | 57° | 135g | ~$100 | Best Overall Ulnar |
| 2 | Razer Pro Click V2 Vertical | SAFEST | Vertical | 30° | 110g | ~$120 | Best Premium Vertical |
| 3 | Evoluent Original Vertical | SAFEST | Vertical | 80° | 175g | ~$110 | Best Maximum Vertical |
| 4 | TECKNET Ergonomic | SAFEST | Vertical | Vertical | 140g | ~$25 | Best Budget Vertical |
| 5 | AOC 2.4GHz Ergonomic | SAFEST | Vertical | Vertical | 120g | ~$30 | Best Mid-Budget Vertical |
| 6 | Logitech MX Master 4 | MODERATE | Sculpted | Palm-down | 134g | ~$120 | Best Premium Sculpted |
| 7 | Logitech MX Master 3 | MODERATE | Sculpted | Palm-down | 141g | ~$100 | Best Productivity Sculpted |
| 8 | Logitech MX Master 2S | MODERATE | Sculpted | Palm-down | 145g | ~$70 | Best Budget Sculpted |
| 9 | Logitech MX Ergo S Trackball | STATIONARY | Trackball | 20° tilt | 259g | ~$100 | Best Premium Trackball |
| 10 | Logitech Ergo M575S Trackball | STATIONARY | Trackball | Flat | 145g | ~$50 | Best Mid-Budget Trackball |
Full Reviews: 10 Best Mouse for Ulnar Nerve Pain Picks
Logitech MX Vertical Ergonomic Wireless Mouse
The Logitech MX Vertical is the universal safest pick for ulnar nerve pain. The 57 degree vertical angle holds your hand in natural handshake position which eliminates the forearm pronation that drives ulnar deviation at the wrist. Premium Logitech build with 4-month battery life. USB-C rapid charging. The most-tested ulnar nerve mouse in 2026.
Bluetooth 5.0 plus USB receiver dual connectivity. Easy-Switch 3 paired devices. USB-C rapid charging. Mac, Windows, Linux, Chrome OS compatible. Best premium vertical for ulnar nerve sufferers wanting Logitech ecosystem reliability with proven biomechanical benefits validated by Human Factors 2008 ergonomic research on vertical mouse posture.
What We Loved
- 57° eliminates forearm pronation
- Reduces ulnar deviation at wrist
- Research-validated angle
- Premium Logitech build
- Easy-Switch 3 devices
- USB-C rapid charging
- 4-month battery life
Watch Out For
- Premium $100 pricing
- Right-hand only design
- 1-2 week adaptation period
- No side scoops for hypothenar
Razer Pro Click V2 Vertical Wireless Mouse
The Razer Pro Click V2 Vertical offers gentler 30 degree slope making transition easier for ulnar nerve users coming from standard mice. 110g lightweight design reduces grip force which reduces ulnar muscle tension. Premium aesthetic suitable for visible home office setups. Razer HyperSpeed 1ms RF latency. Dual Bluetooth plus 2.4GHz wireless connectivity.
Bluetooth plus 2.4GHz HyperSpeed dual wireless. 1ms RF latency. USB-C charging. Multi-device pairing across Mac, Windows, iPad. Premium productivity aesthetic. Best Tier 1 safest premium vertical for ulnar users wanting premium aesthetic and easier vertical transition than aggressive 57+ degree alternatives at competitive premium pricing.
What We Loved
- 30° gentler slope
- 110g lightweight design
- Easier ulnar adaptation
- Premium aesthetic
- USB-C charging
- Multi-device pairing
Watch Out For
- Premium $120 pricing
- 30° less extreme than MX Vertical
- Razer Synapse software needed
- Right-hand only
Evoluent World's Original Vertical Mouse
The Evoluent Original Vertical Mouse uniquely addresses both ulnar nerve aggravators simultaneously. The near-80 degree slope creates perfect handshake position eliminating forearm pronation entirely. The pinky lip cushion lifts the hypothenar (palm heel) away from the desk surface reducing external Guyon's canal compression. Pioneer brand of vertical mouse design since 2002. 3 hand size options for optimal fit.
DPI rocker switch with LED indicator. Middle button for tab opening efficiency. Available wired or wireless. 80 degree near-vertical angle. Pinky lip cushion prevents pinky drag. Best severe ulnar nerve pick for users requiring maximum vertical angle plus pinky lip protection that uniquely addresses both ulnar nerve compression sites.
What We Loved
- 80° maximum vertical angle
- Unique pinky lip cushion
- Addresses both ulnar sites
- 3 hand sizes available
- SERP authority pioneer brand
- 20+ years engineering
Watch Out For
- Premium $110 pricing
- 175g heaviest in Tier 1
- 2-3 week adaptation period
- Most aggressive learning curve
TECKNET Ergonomic Vertical Mouse
The TECKNET Ergonomic Vertical Mouse is the best budget vertical testing pick for ulnar nerve. Sub-$25 pricing makes vertical mouse intervention accessible without significant financial commitment. Genuine vertical design (not just "ergonomic" marketing) reduces forearm pronation. 2.4GHz USB wireless eliminates cable drag. Best entry-level ulnar testing before premium tier investment commitment.
2.4GHz USB receiver plug-and-play wireless. DPI adjustment switch. 6 buttons including back and forward navigation. AA battery powered with 12-month battery life. Multi-OS compatible (Windows, Mac, Linux). Best budget vertical testing pick for ulnar users validating vertical mouse concept at remarkable sub-$25 pricing point.
What We Loved
- Sub-$25 budget pricing
- Genuine vertical design
- 2.4GHz USB plug-and-play
- 12-month battery life
- 6 buttons functionality
- Best testing pick minimum risk
Watch Out For
- Build quality matches budget
- TECKNET brand less established
- AA battery (not rechargeable)
- Limited longevity expectations
AOC 2.4GHz Ergonomic Wireless Mouse
The AOC 2.4GHz Ergonomic Wireless Mouse delivers reliable vertical design at slightly elevated mid-budget pricing. Vertical handshake position reduces forearm pronation and ulnar deviation. 2.4GHz USB receiver wireless connectivity. 120g lighter than TECKNET further reduces grip force during long ulnar-sensitive sessions. AOC monitor industry build quality reputation at budget mouse pricing.
2.4GHz USB receiver plug-and-play wireless. DPI adjustment switch. 6 navigation buttons. 120g lightweight reduces grip force. AA battery with 6-month life. Multi-OS compatible. Best mid-budget vertical for ulnar users wanting AOC reliability at sub-$30 pricing without committing to premium tier investments.
What We Loved
- AOC brand reliability
- 120g lightweight
- Vertical handshake position
- 2.4GHz USB plug-and-play
- Mid-budget pricing $30
- 6 navigation buttons
Watch Out For
- AOC less established in mice
- AA battery powered
- No Bluetooth option
- Limited customization
Logitech MX Master 4 Wireless Mouse
The Logitech MX Master 4 represents Logitech's premium sculpted ergonomic mouse with specific ulnar nerve benefits. The side scoops on both sides lift the hypothenar (palm heel) away from desk surface reducing external Guyon's canal compression. MagSpeed electromagnetic scroll wheel reduces total mouse activity. Easy-Switch 3-device pairing across hybrid setups. Premium build quality.
USB-C rapid charging capability. Bluetooth plus Logi Bolt USB receiver dual connectivity. Logitech Flow cross-device productivity integration. MagSpeed scroll wheel. Best premium sculpted moderate-tier pick for mild ulnar users wanting full Logitech productivity ecosystem at premium pricing with hypothenar contact relief benefits.
What We Loved
- Side scoops reduce hypothenar pressure
- MagSpeed effortless scrolling
- Easy-Switch 3 devices
- USB-C rapid charging
- Logitech Flow integration
- Premium build quality
Watch Out For
- Forearm pronation remains
- Premium $120 pricing
- 134g heavier than gaming mice
- Mild ulnar cases only
Logitech MX Master 3 Wireless Mouse
The Logitech MX Master 3 delivers the original premium sculpted design with side scoops plus comprehensive productivity features. 7 customizable buttons including gesture button. Dual MagSpeed scroll wheels (vertical and thumb horizontal). Side scoops on both sides lift hypothenar from desk reducing Guyon's canal external compression. Best productivity-focused sculpted pick for mild ulnar nerve users.
Bluetooth plus Logi Bolt USB receiver dual connectivity. 4000 DPI sensor. USB-C charging with 70-day battery. Easy-Switch 3-device pairing. Logitech Flow cross-device productivity integration. Best productivity sculpted moderate-tier pick for mild ulnar users wanting comprehensive Logitech feature set at competitive premium pricing.
What We Loved
- Side scoops reduce hypothenar pressure
- 7 customizable buttons
- Dual MagSpeed scroll wheels
- Gesture button
- USB-C charging
- Easy-Switch 3 devices
Watch Out For
- Forearm pronation remains
- 141g heavier weight
- Mild ulnar cases only
- Right-hand only design
Logitech MX Master 2S Bluetooth Edition Wireless Mouse
The Logitech MX Master 2S delivers proven sculpted side scoops design at accessible mid-budget pricing. Side scoops lift hypothenar reducing Guyon's canal external compression. Hyper-fast scroll wheel reduces total ulnar muscle activation. Years of established refinements ensure reliability. Best proven budget sculpted pick for mild ulnar users wanting Logitech ecosystem at lower investment.
Bluetooth wireless plus USB Unifying receiver dual connectivity. Easy-Switch 3-device pairing. 4000 DPI sensor. Hyper-fast scroll wheel with click-to-shift modes. 70-day battery life. Best proven mid-budget sculpted pick for mild ulnar users wanting established Logitech ergonomic design at accessible pricing without committing to premium MX Master 4 investment.
What We Loved
- Side scoops reduce hypothenar pressure
- Proven sculpted design
- Mid-budget $70 pricing
- Hyper-fast scroll wheel
- 70-day battery life
- Multi-OS compatibility
Watch Out For
- Forearm pronation remains
- 145g heaviest in MX line
- Older USB micro-B charging
- Mild ulnar cases only
Logitech MX Ergo S Advanced Wireless Trackball Mouse
The Logitech MX Ergo S Trackball uniquely eliminates ulnar deviation through stationary wrist position. The wrist stays motionless while thumb operates trackball. This stationary positioning prevents the ulnar deviation that compresses Guyon's canal at the wrist. Adjustable 20 degree tilt reduces forearm pronation partially. Premium Logitech build with USB-C charging and Easy-Switch 2-device pairing.
Bluetooth plus Logi Bolt USB receiver dual connectivity. USB-C charging with 4-month battery life. Easy-Switch 2-device pairing. Precision mode button for detailed work. Best premium trackball for severe ulnar users wanting stationary wrist position benefits at premium tier with comprehensive Logitech ecosystem features.
What We Loved
- Stationary wrist eliminates ulnar deviation
- Adjustable 20° tilt
- Premium build quality
- USB-C rechargeable
- Precision mode button
- Easy-Switch pairing
Watch Out For
- Premium $100 pricing
- 259g heaviest in this guide
- Thumb trackball adaptation
- Easy-Switch only 2 devices
Logitech Ergo M575S Wireless Ergonomic Trackball Mouse
The Logitech Ergo M575S Trackball provides stationary wrist position at accessible mid-budget pricing. The wrist stays motionless while thumb operates trackball. Eliminates ulnar deviation that compresses Guyon's canal. 18-month battery life on single AA battery. Multi-OS compatibility with Bluetooth plus USB receiver. Best entry trackball for ulnar users testing stationary trackball concept before premium investment.
Bluetooth wireless plus USB receiver dual connectivity. 18-month battery life on 1 AA battery. Multi-OS compatibility (Windows, Mac, Linux, ChromeOS, iPad). 145g moderate weight. Best mid-budget trackball for ulnar users prioritizing stationary wrist benefits at accessible pricing without committing to premium MX Ergo S features and pricing.
What We Loved
- Stationary wrist position
- Mid-budget $50 pricing
- 18-month AA battery
- Multi-OS compatibility
- Logitech ecosystem
- Eliminates ulnar deviation
Watch Out For
- Flat design (no tilt)
- Thumb trackball adaptation
- Heavier 145g
- AA battery (not rechargeable)
Mice and Habits to AVOID for Ulnar Nerve Pain
Beyond choosing the right mouse, ulnar nerve sufferers must avoid specific mice and desk habits that aggravate cubital tunnel and Guyon's canal compression. The patterns below consistently worsen ulnar nerve symptoms regardless of which mouse you choose. Avoiding these is as important as picking the right mouse for genuine ulnar nerve relief.
AVOID for ulnar nerve pain:
- Resting elbows on hard desk edges: Direct cubital tunnel compression from elbow contact with hard surfaces is the #1 ulnar aggravator. Use elbow pads or repositions to avoid.
- Tiny travel mice forcing pinch grip: Compact mice force hand into pinched position that compresses ulnar muscles. Use only briefly during travel.
- Standard flat mice over 130g: Heavy flat mice maintain pronation plus require higher grip force compounding ulnar deviation pressure.
- Sleeping with bent elbow under head: Prolonged elbow flexion during sleep compresses cubital tunnel for hours. Use straight-arm sleep position or splint.
- Resting pinky on desk while using mouse: Hypothenar contact with hard surface externally compresses Guyon's canal during mouse use.
Profession-Specific Ulnar Nerve Picks
Different professions face different ulnar nerve risk patterns. Match your specific profession to the appropriate recommendation below. Software developers face it from elbow-resting habits. Designers face it from prolonged mouse precision work. Use the framework below to identify the right mouse for your specific ulnar nerve risk pattern in 2026.
Graphic Designer
Precision mouse work. Prolonged static position.
When to See a Doctor
Mouse modification alone cannot treat established ulnar nerve entrapment. Mouse changes prevent further aggravation and support recovery alongside medical treatment. For diagnosed or suspected ulnar nerve entrapment, medical consultation is essential regardless of mouse choice. The signs below indicate professional medical evaluation is required, not just better mouse selection.
See a physician or certified hand therapist if:
- Pinky and ring finger numbness persists beyond 2 weeks despite mouse modifications
- Hand weakness affecting grip strength or fine motor control
- Visible thinning of hypothenar muscles (palm heel)
- Pain extending from inner elbow up the inner arm
- Difficulty crossing fingers or pinching with pinky
- Symptoms wake you at night or limit sleep
- Persistent tingling regardless of arm position
- Drop objects from weakened pinky/ring fingers
Medical treatment may include: nerve gliding exercises, elbow splinting at night, cortisone injection, physical therapy, or in rare cases surgical decompression. Combine medical treatment with proper ergonomic mouse selection for comprehensive recovery.
Frequently Asked Questions
Final Verdict: Choosing Your Best Mouse for Ulnar Nerve Pain
The right best mouse for ulnar nerve pain in 2026 depends on your symptom severity, budget, and hand size. For most ulnar nerve users, the Logitech MX Vertical at $100 (Tier 1 Safest) delivers the optimal balance of 57 degree vertical angle eliminating pronation, Logitech ecosystem reliability, and Easy-Switch multi-device pairing. The safest pick for the broadest range of ulnar nerve symptoms from mild prevention to moderate intervention.
For severe ulnar symptoms requiring maximum intervention, the Evoluent Original Vertical at $110 with 80 degree maximum angle plus unique pinky lip cushion addresses both ulnar compression sites simultaneously. For premium aesthetic with gentler 30 degree slope, the Razer Pro Click V2 at $120. For budget vertical testing, the TECKNET at $25 or AOC 2.4GHz at $30. All Tier 1 picks eliminate forearm pronation critical for ulnar nerve recovery.
For mild ulnar users wanting premium sculpted with side scoops (not vertical), the Logitech MX Master 4 at $120 or MX Master 3 at $100 or MX Master 2S at $70. For severe ulnar users wanting stationary wrist position via trackball, the Logitech MX Ergo S at $100 or budget M575S at $50. Tier 3 trackballs uniquely eliminate ulnar deviation through stationary wrist positioning.
Whichever pick you choose from this best mouse for ulnar nerve pain guide, remember that mouse modification alone cannot replace medical treatment for diagnosed ulnar nerve entrapment. Combine your ulnar mouse with medical evaluation, comprehensive wrist pain intervention, proper elbow positioning, ergonomic keyboard pairing, and elbow pad if you have elbow-resting habits. For specific guidance see our CTS mouse hub, De Quervain mouse hub, or our complete six-leg desk worker wellness system.
Build the complete ulnar nerve recovery system: See our ergonomic mouse hub for related wrist-protection guidance. See CTS mouse hub for nerve compression. See De Quervain mouse hub for thumb pain. See tendonitis mouse hub for related conditions. See silent mouse hub for noise reduction. See MX Vertical vs MX Master 3 for head-to-head. See trackball hub for stationary alternatives. See wireless keyboard hub for ergonomic keyboard pairing. See complete WFH hub for the full ergonomic ecosystem.
Continue Building Your Ulnar Nerve Knowledge
Ergonomic Mouse Hub
Comprehensive wrist intervention.
CTS Mouse Hub
Carpal tunnel mouse guide.
De Quervain Mouse Hub
Thumb tendon protection mice.
Tendonitis Mouse Hub
Related tendon condition mice.
Silent Mouse Hub
Decibel-tested silent mice.
MX Vertical vs MX Master 3
Head-to-head comparison.
Trackball Mouse Hub
Stationary trackball alternatives.
Vertical Mouse Education
How vertical mice work.
Vertical vs Regular
Mouse category comparison.
Large Hands Vertical
Hand size fit guidance.
Wireless Keyboard Hub
Pair with wireless keyboard.
Complete WFH Hub
Full ergonomic ecosystem.