[4 in 1 Bluetooth Transmitter] It is a Bluetooth transmitter and a Bluetooth receiver. In TX mode, the bluetooth adapter converts wired audio source to wireless audio for bluetooth speaker/etc bluetooth audio output. In RX mode, the Bluetooth receiver supports wired audio output from CD players/home audio/car audio, and plays wireless audio from Bluetooth audio sources such as mobile phones. [KTV singing, FM radio function] It has RCA and AUX input and output connections, and supports FM antenna, Bluetooth antenna and 6.5mm microphone interface. Compatible with 99% TVs, suitable for family KTV singing parties [Low-Latency DSP Decoding] The Bluetooth adapter is equipped with a Bluetooth 5.1 chip with DSP low-latency Bluetooth codec, which can reduce the delay from 220ms to less than 40ms. [Long battery life] Equipped with a 1200mAh rechargeable battery, it only takes 1.5h to fully charge, and supports a maximum working time of 8 hours. Standby time up to 300 hours.