Lenovo Essential Wireless Combo Keyboard & Mouse Gen2 Black; Battery Life: Up to 15 months battery life for keyboard(may vary based on usage) Up to 18 months battery life for mouse (may vary based on usage); Mouse Sensor: Optical Sensor; Scrolling: 2-way scrolling (Up, Down); Packed Dimensions (L x D x H): 520 x 142 x 42 mm / 20.47 x 5.59 x 1.65 inches; Connection Type: 2.4G; Warranty Period: 3 Years;