Tape design with strong Bluetooth-compatible function, you can insert the cassette into the car cassette player, then connect it with your phone Bluetooth, enjoy the music and hands-free freely and instantly. Built-in microphone, the tape converter supports hands-free calling, easy to answer or end a call with one-key. You don't need to hold the phone while driving or walking in the way. Adopt the latest 5.0 Bluetooth-compatible chip, provides more stable performance, steadier and better calling quality, compatibility and stronger functions, supporting you clear, long lasting and continuous phone call and stereo music. The cassette has USB ports and built-in 130mAh rechargeable battery, safe and , you can charge the lamp anytime by connecting with power bank, laptop or other kinds of USB adaptor, convenient to use. Suitable for placing in the car, auto and vehicle to enjoy music, hands-free calling and other Bluetooth-compatible functions. Bluetooth-compatible version: 5.0 Power supply: USB Battery: built in 130mAh rechargeable battery Size: 10 x 6.3 x 0.7cm/3.93 x 2.48 x 0.27inch Weight: 1240g color:Black Material:ABS Package Contents: 20 x cassette adapter 20 x USB cable Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.