Connection Type: Wireless, Layout: English, Mouse: Sensor technology: High Precision Optical Tracking, Sensor resolution: 1000 dpi, Number of buttons: 3, Scroll wheel: Yes- Mechanical, Scroll Buttons: Middle Button, Battery life Mouse: 18 months, Battery type mouse: 1xAA, Keyboard: Battery life Keyboard: 36 months, Battery type keyboard: 2xAAA, Wireless operating distance: 10 m 4, Wireless technology: Logitech Nano Receiver