. RF Frequency 2.4 GHz Sensor engine BlueEye Resolution (DPI) 1200 Number of buttons 3 (left, right, middle button with scroll) Battery type Built-in rechargeable NiMH (Before first use, fully charge the battery for 10 hours uninterrupted.) Other - Weight (g) Approx. 81 g (includes receiver & rechargeable NiMH) Dimensions (W x H x D) mm (inches) 59.5 x 106 x 37.1 mm (2.34 x 4.17 x 1.46 inches) System requirements Windows 7, 8, 8.1, 10 or later / macOS X 10.7.4 or later Colors Gold / Silver / Iron Gray / Coffee / Chocolate What's included ECO-8015 (Built-in Rechargeable NiMH Battery)  Pico receiver x1  Micro USB cable x1  Multi-language quick guide