Feature: 1. Compatible: Sound receiver adapter to easily add BT to your car speaker system, home stereo, speakers, wired headphones via 3.5mm AUX socket. Slim design, compact and does not take up space. meet your usage needs. 2. Stable And Low Latency: Sound receiver transmitter adopts BT 5.0 communication standard, with low latency, noise reduction, 15m transmission distance, large range coverage, fast and stable connection, and wireless is more free. 3. NFC Function: Sound adapter supports NFC pairing. When pairing, the NFC of the phone is turned on, and the BT 21 model will appear when the mobile phone is close to the product. Click to connect, and it will automatically reconnect when it is used again. 4. Easy To Use: 2 in 1 sound adapter, one button control, AUX, RCA connectors. These two interfaces support BT sound receiving and transmitting functions. Plug and play, easy to set up, one key operation, clear status indicator. 5. HiFi Sound Quality: Wireless sound receiver transmitter adopts HiFi decoding IC to ensure that BT is not distorted, listening to songs is not stuck, low latency, HiFi sound quality allows you to experience perfect music. Specification: Item Type: Sound Receiver Adapter Material: ABS Transmitter Interface: AUX RCA Model: BT 21 Output Impedance: 75 Ohms Frequency Response Range; 10HZ - 20KHZ Decoding IC: for Jerry IC Signal Noise: >90 DB Effective Open Space: Approx. 15m/49.2ft BT Version: 5.0 Performance: Stereo HiFi Class Built in Battery Type: Li Ion Battery Battery Model: 502030 Battery Capacity: 200mAh. Package List: 1 x BT Sound Receiver Adapter1 x 3.5mm Male to Male Cable1 x USB to Type C Charging Cable1 x RCA One for Two to 3.5mm Male Cable 1 x Chinese and English Manual