The usb bt400 is a bluetooth smart ready usb adapter with new bluetooth 40 capabilities it connects you with a multitude of compatible devices and supports bluetooth low energy ble to reduce power consumption in dual mode the usb bt400 maintains full backward compatibility with bluetooth 30 21 and 20 the asus usb bt400 provides new and advanced bluetooth 40 and enables wireless connectivity with a wide range of devices such as computers printers phones headsets speakers keyboards controllers a