Tape design with strong Bluetooth function, insert the cassette into the car cassette player, then connect it with your phone via Bluetooth to enjoy music and hands-free calling. Built-in microphone supports hands-free calling, easy to answer or end a call with one button. No need to hold the phone while driving or walking. Features the latest Bluetooth 5.0 chip for stable performance, steady calling quality, improved compatibility, and stronger functionality, delivering clear, long-lasting, and continuous phone calls and stereo music. The cassette includes USB ports and a built-in 130mAh rechargeable battery, safe and durable, allowing you to charge the device anytime using a power bank, laptop, or other USB adapter. Convenient for use in cars and vehicles to enjoy music, hands-free calling, and other Bluetooth functions. Bluetooth 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: 62g Color: Black Material: ABS Package Contents: 1 x Cassette adapter 1 x USB cable Note: Light reflection and different displays may cause the color of the item in the picture to differ slightly from the actual product. Measurement may vary by +/- 1-3cm.