LEFT-HANDED ERGONOMIC VERTICAL MOUSE - Specifically-designed for left-handers, encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. Recommended to Repetitive Strain Injuries RSI User and user works particularly long periods on the computer.( 2 AAA batteries needed, not included )The usb receiver for the mouse is in a small transparent bag inside the box, thanks!! EASY TO USE, PLUG & PLAY - Strong and reliable 2.4GHz wireless connection, one USB receiver at the bottom of mouse, just Plug and Play! The usb receiver for the mouse is in a small transparent bag inside the box, thanks!!. The left-handed mouse dimensions: 5.0*3.0*2.5 inches. NOT compatibility with Mac OS MULTIFUNCTION AND CONVENIENT - Easy access to multiple usage 3-level DPI (800/1200/1600) suit both ordinary and gaming needs, with premium optical engine, allows quicker response, smoother tracking and higher precision movement. POWER-SAVING