At last a sized mouse that fits like a glove! The HandShoe Mouse is developed in close cooperation with two medical universities. The concept of the patented HandShoe Mouse is to prevent excessive gripping and pinching as well as the stretching of the fingers. The special shape allows for the hand to continuously rest on the mouse body in a relaxed fashion and thereby reducing the risk of RSI (repetitive strain injury). Available in three sizes for the right hand. Now available in a BlueRay Track version which works on almost every surface without a mouse mat! Features: Provides full support of the hand and wrist. No friction between the skin of your hand and the desktop Available in three sizes for the right hand. Measure hand from the first crease in the wrist to the end of the ring finger with the hand in a stretched position. Medium = 6 3/4" - 7 1/2" Two button mouse with scroll wheel (Large version 3 buttons) Compatible with Windows 95, 98, 2000, NT, XP,or Vista, Windows 7 / MAC: OS 9, OS X / Unix Plug & Play - no special software required BlueRay Track technology makes it work on almost every surface without a mouse mat. No performance degradation due to dirt buildup like "ball" style mechanisms. Wired and wireless version Color: black More Information about the wireless version Poll rate (Hertz) of the electronics is 113~118Hz and up to 120Hz. Wireless range of the receiver is 10 m Receiver / dongle is fitted with a LED light which goes on and off when operating the mouse. The wireless HandShoe Mouse uses a lithium ion battery which can only be removed by professional service providers. Battery life is around 2 years. Operating time for the wireless version is around 4 weeks. Charging of the wireless version takes around 3 hours. Charging takes place by means of USB cable; The PC or laptop needs to be switched on during charging. One can continue working while charging the battery; the micro receiver / dongle must be in place. - Provides full support of the hand and wrist. - Available in three sizes for the right hand. Measure hand from the first crease in the wrist to the end of the ring finger with the hand in a stretched position. - Medium = 6 3/4" - 7 1/2" - BlueRay Track technology makes it work on almost every surface without a mouse mat. - wireless version