Tape design with strong Bluetooth function. Insert the cassette into the car cassette player and connect it to your phone via Bluetooth to enjoy music and hands-free calling instantly. Built-in microphone supports hands-free calling. Answer or end calls with one button. No need to hold the phone while driving or walking. Features the latest Bluetooth 5.0 chip for stable performance, improved call quality, wider compatibility, and enhanced functionality. Supports 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 design. Charge the device using a power bank, laptop, or any 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 (ABS) Package Contents: 1 x Cassette adapter 1 x USB cable Note: Light reflection and different displays may cause slight color variation. Measurement error is +/- 1-3cm.