2-IN-1 DESIGN. Powered by the premium CSR8670 chipset, TROND BT-DUO II could be switched easily between the transmitter (TX) mode and the receiver (RX) mode. You can pair the transmitter with your wireless headphones and watch TV shows late at night. Or you can use it as a Bluetooth receiver, and enjoy CD-quality music wirelessly from your phone to your wired home stereo system DUAL LINK & NO LIP-SYNC DELAY. What really makes TROND BT-DUO II stand out is that it supports dual link aptX Low Latency when pairing two Bluetooth headphones simultaneously to BT-DUO II. This way, both you and your significant other could either watch TV shows late at night or enjoy movies from your iPad on the plane without any noticeable audio lag. You may order one or two TROND TD-BH01 Over-Ear Bluetooth Headphones for the best low latency performance OPTICAL, 3.5mm AUX & RCA. TROND BT-DUO II provides up to 3 types of audio connections: 3.5mm aux, white/red RCA (via the included 3.5mm to RCA cable adapter), TOSLINK. More flexibility for you to connect your devices via different cables. Please note that this transmitter/receiver doesn't function as an audio converter; the digital optical port is only for audio input purpose, and can only be used in the transmitter (TX) mode