ERGONOMIC DESIGNED WIRELESS MOUSE : Ergonomic vertical design encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. It provides better support and accommodates your hand in a natural position, relieves pressure in wrist joint and reduce risk of cramping. HIGH-CAPACITY RECHARGEABLE BATTERY : Built-in rechargeable battery, easily recharged through the included USB cable, no need to change the battery, very convenient! EASY TO USE -- One nano USB receiver at the bottom of the mouse, Just Plug and Play !