ASUS USB-BT400 USB 2.0 Bluetooth 4.0 Adapter. Advanced Bluetooth 4.0 adapter, backward compatible with Bluetooth® 2.0/2.1/3.0. Enables wireless communication with Bluetooth-enabled computers, printers, phones, headsets, speakers, keyboards, controllers, and more. Bluetooth Low Energy technology for energy-saving wireless connectivity. Highly portable ultra-small design.