Specification: Item Type: BT AUX Adapter_x000D_Material: PVC_x000D_BT Version: 5.1_x000D_Connection Range: Approx. 15m/49.2ft_x000D_Battery Capacity: 140mAh Lithium ion Battery (Shipped with Battery)_x000D_Frequency Response Range: 10Hz-20kHz_x000D_SNR: Less Than 110dB Features: 1[Enjoy Wireless Music] This car BT adapter can connect non BT car stereo systems, home stereo, speakers, wired headphones, etc, via a 3.5mm/0.1in AUX plug. 2[Stable And Fast] Equipped with BT 5.1 chip, stable connection, fast transmission speed and wide signal range, just pair it with your phone and start listening to your favorite music. 3[Rechargeable] This BT transmitter receiver has a built in 140mAh large capacity rechargeable lithium ion battery, and can be used while charging, very convenient. 4[Easy To Use] The car BT adapter has a built in microphone and a multi function button, so you don't have to look down at your phone while on the move, ensuring you drive safely. 5[Equipment Upgrade] You can easily upgrade the sound equipment without BT function to BT equipment, one key switch, small and portable, with high quality PVC shell, durable. PackageList: 1 xBT AUX Adapter 1 x 3.5mm Plug 1 x Type C Charging Cable 1 x Manual