ALLIMITY Bluetooth Transmitter Receiver 3.5mm Wireless Audio Adapter for Speaker/Headphone, Computer/TV/PC, Mp3/Mp4 Player, Home/Vehicle Audio Stereo System 1. Simple one-button switch to shift between transmitter(TX) and receiver(RX) mode. Bluetooth transmitter and receiver, Transmitter function transforms 3.5mm audio-out media devices into a Bluetooth device capable of streaming Bluetooth audio; Receiver lets non-Bluetooth devices like car or home stereos receive high quality audio. 2. What is TX function? This 2 in 1 bluetooth transmitter add bluetooth capability to your None-Bluetooth audio source device like TV, iPod, CD player, PC, MP3/MP4 player and transmit audio to your bluetooth headphone, speaker and other stereo system 3. What is RX function? This device function as a bluetooth receiver compatible with most smartphones, ideal for home or vehicle stereo systems. it receives audio signal from devices like smartphones and then transmit it to those none bluetooth enable devices, like home or vehicle audio systems, and play it loud 4. Built in battery for portable use; Battery life for TX mode: about 8 hours; battery life for RX mode: about 6 hours. Charging time:1-2 hours. 5. Important: If you were not sure how to get allimity products to work, please kindly contact our customer support team for quick solutions or read the description below before leaving us a feedback or review, we will try our best to help you. Thanks! Package contents: allimity Bluetooth Transmitter/ Receiver, 3.5mm Audio Cable, USB Charging Cable, 3.5mm Red and White AV Cable, User Manual.