Built-in rechargeable lithium battery:Rii K22 Dual Mode Wireless Bluetooth Keyboard The wireless Bluetooth Multi-Device keyboard is a built-in lithium rechargeable battery with an industry-high capacity, and charging by Type-C charger Easy-switch stable Bluetooth & multi-device connection: Connect up to 2 devices simultaneously and switch between them easily. the Bluetooth and 2.4G Wireless keyboard will keep your desktop clutter-free Simple Plug and Play:Simply plug the usb receiver into a USB port and the wireless touchpad keyboard is ready to go.The Bluetooth keyboard has a 10 meters (33ft) bluetooth range, Ensures trouble free connection in the largest room Ergonomic Design:Rii K22 Wireless Bluetooth keyboard is constructed of the high quality stainless steel and ABS,Easy to carry around your home for familiar typing in any room