M355 Specifications Sensor: Optical DPI: 800-1200-2000-3000-6400 (default) Buttons: 9 (programmable) Switch rating: 5 million clicks Backlight: 7 colors Polling rate: up to 1000 Hz Interface: USB 2.0 Cable length: 1.5 m OS support: Windows 7 or newer Feature High-profile design with optimum full palm support Fast Key to execute a double click with only one key press Advanced customization software 7 colors backlight