With its built-in wrist support and neutral grip, the ergonomist-approved Pro Fit Ergo Wireless Mouse positions your hand for improved comfort. Features include dual wireless (2.4 GHz and Bluetooth 4.0 LE) with 128-bit AES encryption security, quiet clicking, five buttons (including forward and back), a replaceable receiver*, a three-mode power-saving switch, and three DPI settings (800/1200/1600). * In the event the receiver is lost or damaged, simply purchase a new one, pair it with your mouse, and you?re all set.