Lenovo Professional Wireless Rechargeable Combo Keyboard and Mouse - Overview and Service Parts; Mouse Resolution: 3-level Adjustable (default at 2400, 1600, 800) ; Levels can be configured via Lenovo Go Central Software up to 4000;Scrolling: 4-way scrolling (Up, Down, left, right); Number of Button: 8 buttons (Left / Right Click, DPI Button, Forward Button, Backward Button, Power Switch, Multi-Device Switch, Scroll-wheel with middle click and right/left-tilt); Connectivity: 2.4G & Bluetooth; Special / Added Features: rogrammable Keys / Lithium battery/Seamless switch up to 3 devices / Dual mode connections : 2.4G & Bluetooth / Dynamic Wheel / Bio-rubber coated grip; Color: Grey; Battery Charging Time : 2hours for full charge; Backlight: NO