With the BT 4.0 cassette adapter, your tape deck player immediately becomes a BT wireless cassette player, used in your car or home system. Stream music from any BT-enabled device, such as iOS, Android-based electronics, Tablet PC, etc | Hands-free Function: Built-in microphone, you can put your hands on the steering wheel while driving, realize hands-free mobile phone call safely at the same time | Better Sound Quality: Use CSR high quality chip. The audio tape is equipped with a stereo two-channel audio cassette head to improve the playback quality. The sound qulity will be influenced by the age of cassette tape player. When using too old player, there may be noise | Latest Version for Seamless Pairing: Wider range and lower power consumption. Automatically reconnect when booting | Long Playing Time: The tape adapter with built in lithium rechargeable battery. USB charge. Can work 4-5 hours continuously after fully charged, perfect for long road trip