Features: 1. USB interface, plug and play 2. Ergonomic, arc shape fits the palm, suitable for left hand 3. The special counterweight design makes the center of gravity design in the palm of the hand, which makes the operation more stable 4. Precise and sensitive optical engine, sensitive and precise optical positioning 5. Adopting advanced and high-frequency optical positioning technology with a resolution of 1000-1200-1600DPI, allowing you to use it steadily and freely on desktops other than glass, and do whatever you want 6. The wheel scrolls without noise, the paragraph feels soft, the reaction is quick and accurate, and it can effectively scroll the screen up and down, easily browse and edit web pages, data tables, photos, etc. 7. The mechanical life and electrical life of the keys are over 5 million Product parameters: 1. Size: 7x12x6cm 2. Weight: 87g 3. Operating distance: 10m 4. Number of keys: 3 keys 5. System: Windows ME / 2000 / XP / VISTA / Windows 7 / Linux 2.4 / Mac Note: Batteries need to be purchased separately