Ergonomic Design The ergonomic upright mouse offers your hand maximum support, encourages natural handshake mouse holding. Best care of your wrist and palm, Stop hurting your hand. Dimension: 4.1*2.7*2.3 inches. HIGH-CAPACITY RECHARGEABLE BATTERY Built-in rechargeable battery. You no longer need to buy batteries, durable and Eco-friendly, very convenient!! EASY TO USE - One USB receiver at the bottom of mouse, Just Plug and Play!