NOTE: BTR005BK is not a Bluetooth transmitter > so it CAN NOT pair with Bluetooth headphones/speaker or airpods. Compatible with the general aux 3.5mm headphone jack (Not available for four-pole pins or recessed port.). ✓ PORTABLE & EASY TO USE?This Bluetooth aux receiver is super simple to set up, one key to power on and enter pairing mode automatically. The car bluetooth adapter aux will automatically connects to your phone when you just turned it on. ✓ WORKING WHILE CHARGING?This Aux to Bluetooth adapter for car is compact size, but the battery last 5 hours which is pretty decent for use and it also works whilst being charged. ✓ SMART BLUETOOTH 5.0?The Bluetooth audio adapter equipped with Bluetooth 5.0 to ensure faster transmission and maintains a steady connection up to 50 ft in open area. The sound is absolutely crystal clear with a perfect tone, enjoy Wireless Streaming Music. ✓ HANDS-FREE CALL CALLING?This car Bluetooth receiver built-in with microphones can be used to answer hands-free calls. Small and neat aux Bluetooth car kits for road trips to enjoy music or call in your car without using a cable. Make your life super easier from now on. ✓ UPGRADE OLD STEREO?This Bluetooth 3.5mm Aux adapter can be connected to non-Bluetooth car stereo or any other stereo home wired speaker headphone etc. You can just plug it into anything that has a 3.5mm input port (make SURE it is INPUT) and play your tunes from your smart phone or other Bluetooth Source devices.