A Bluetooth 4.2 transceiver with volume control. Turn a TVs audio to wireless and connect to a set of Bluetooth headphones or turn any powered speakers/amplifier wireless and connect audio from a phone to any amplifier. Bluetooth® Profiles: A2DP and AVRCP is supported. An Apt-x® decoder CSR™ has been used for low latency for HD audio quality. This unit can be powered from a suitable USB power supply or the units internal battery which has a 20 hour battery life. Volume can be controlled from the touch buttons found on the top face. There are SPDIF and 3.5mm jack audio connection on the side.