Maximum Hand-Feeling The wireless mouse size is only 4.3 x 2.5 x 1.1 inches (length x width x height), slim wireless mice shape, sweat-resistant and skin-friendly finish are for maximum comfort and support. The thoughtful ring and little finger rest provide extra comfort. The sturdy scroll wheel with metal makes sure that your hand will not slip when scrolling. Strong Durability & Long Working Life The cordless mouse passed 5 million times keystroke test to guarantee extra durability. This cordless mice will enter smart sleep mode after 15 minutes of standby lengthens the battery life, Press any button to wake it up. Note: Powered by 2*AAA battery (Not include battery).