NoCharging Design Insert the BT car adapter into your car's integrated TF card slot and enjoy music streaming and hands calls without charging cables or wiring. No separate power supply is required for basic use. Advanced Music Technology Automatically identifies and delivers audio from TF cards of various brands, ensuring clear, quality sound. Provides seamless playback and reliable performance with minimal setup. Adjustable Frequency Transforms any car stereo into a Bluetoothenabled system. Use the FM transmitter to tune to a frequency between 87.5 and 108 MHz for wireless music streaming from Bluetooth devices or TF cards. Calls Builtin microphone and speakerphone enable answering or rejecting calls effortlessly. Stay focused on the road while dialing and enjoying clear, hands conversations. Key benefits Convenience: no charging or wiring needed; plug and play in the TF card slot. Compatibility: supports TF cards from various brands and Bluetoothenabled devices. Sound quality: automatic optimization for strong, clear audio on the road. Versatility: converts your car stereo to Bluetooth streaming with an adjustable FM frequency. Safety: hands calling helps you stay focused while driving. Use scenarios Daily commute: insert a TF card loaded with music and pair your phone to stream wirelessly while taking calls safely. Cars without Bluetooth: use the FM transmitter to connect your phone to the car stereo for music and hands calls. Shared vehicles or rental cars: quickly enable Bluetooth playback and calling by inserting the adapter into the TF card slot and tuning to an available FM frequency. Compatibility and performance notes Function: Bluetooth streaming and hands calling via FM transmission and TF card playback. Frequency range: 87.5 to 108 MHz for flexible tuning. Input methods: TF card playback and Bluetooth device pairing. Builtin components: microphone for receiving calls and speakerphone for clear audio.