Built-in wrist rest and neutral grip supports, cushions, and positions the wrist for comfort and neutral hand alignment. Dual wireless with 128-bit AES encryption security delivers the flexibility of 2. 4 GHz and Bluetooth 4. 0 LE, with Government-grade encryption. Quiet clicking makes for smooth and non-disruptive operation. Three-mode power-saving switch allows you to toggle between 2. 4GHz, Bluetooth, and off for best battery life. Three DPI settings (800/1200/1600) let you dial in the sensitivity and precision of your mouse cursor. Free downloadable KensingtonWorks software provides button customization