Ergonomic Design & Size - The real ergonomic shape fits your hand very well, designed with thumb and finger rest, which keeps your wrist/arm being in nature position and alleviates the strain/pain on your wrist. It fits better for /Men hands, maybe NOT very comfortable for Women/Small hands. (Right-handed)Silent Click - Left and right click is silent (NOTE: other buttons are general), which makes you conveniently work without disturbing others in the evening, or in the library/the coffee house/the office.Rechargeable & Wireless - Built-in rechargeable Li-battery. This ergonomic mouse lasts about 12-20 days under moderate use after fully charged. The backlight can be separately controlled. It works while charging. 2.4G wireless connection, no wire hassle.3 DPI Levels & Compatibility - 800/1200/1600 DPI (slow to fast), adjusted via DPI button. Plug and play. Compatible with Windows 8/7/10/Vista/XP/2000, , Linux (NOTE: The side forward/backward button is not recognized on ).SpecificationsBattery Capacity: 400mACharging Time: about 2 hoursDPI: 800-1200-1600: 5-million timesCompatibility: Windows, Linux, (The forward/backward button is not recognized on )Colour:BlackMaterial:ABSSize:12.3x8.9x7.2cmPackage Contents:1* wireless mouse1* USB charging cable1* English manualOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.