DUAL-FUNCTION FOR APPLICATION: USB and 3.5 audio jack can be used for audio transmission, which can be applied to more audio devices, and USB power supply without worrying about charging problems. THROW AWAY THE CABLES, FREES THE AUDIO: Either connect audio from , airplane entertainment, fitness equipment, gaming equipment, cars, sound card to wireless Bluetooth headphones or stream audio from cell phones, laptop, computers, CD's to your home/car speaker system. SYNCHRONIZED TRANSMISSION WITH LOW-LATENCY: low-latency technology eliminates Bluetooth audio latency for more stable audio transmissions, enabling synchronized video and audio transmission for both program enjoyment and privacy protection. UPGRADE 4-IN-1 USB BLUETOOTH TRANSMITTER RECEIVER: Integrates 4 kinds of modes - Bluetooth receiving, Bluetooth transmitting, PC transmitting, and external sound card - in 1 Bluetooth transmitter, switching is possible with one button. COMPACT DESIGN FOR EASY CARRYING: The size is only the same size as USB flash disk, easy to carry around, Bluetooth 5.1 technology can realize indoor positioning error within 1m, transmission distance in the absence of obstacles 10-20M meters.