Features 1、FM transmitter, suitable for iPhone/iPod/HTC/MP3/MP4 player and most devices with 3.5mm audio jack. 2、Built‑in 300mAh rechargeable battery for 10 hours of continuous playback. You can enjoy your favorite music on the trip without any worries. 3、Supports FM's last frequency memory function and uses PLL phase‑locking technology to ensure stable output under all conditions. 4、Support hands‑free call through car stereo speakerphone for safe driving. 5、Built‑in digital tube display, easy to read, will not cause distraction in the car. Left and right buttons to adjust the FM frequency, easy to use. Specification It's easy to use, plug the transmitter into your phone or other device, and set the transmitter to the same channel as the car radio. With a launch distance of 15 meters, it is the most powerful transmitter. Features: 1. FM transmitter, suitable for iPhone/iPod/HTC/MP3/MP4 player and most devices with 3.5mm audio jack. 2. Built-in 300mAh rechargeable battery for 10 hours of continuous playback. You can enjoy your favorite music on the trip without any worries. 3. Supports FM's last frequency memory function and uses PLL phase-locking technology to ensure stable output under all conditions. 4. Support hands-free call through car stereo speakerphone for safe driving. 5. Built-in digital tube display, easy to read, will not cause distraction in the car. Left and right buttons to adjust the FM frequency, easy to use. 6. Suitable for iphone series/ipod series / Nokia /Ericsson/HTC/Motorola/Dopod/Xiaomi/LeTV, MP3/MP4/MP5, computer, etc. As long as there is a 3.5MM headphone jack interface machine. Specifications: Charging: 5V 1A (4.75V-5.5V 1A ± 10%) AUX connection: 3.5mm audio connector FM display: 88.1Hz-107.9Hz FM connection: the same frequency is connected Audio input: 3.5mm audio connector Volume adjustment: none Switch: ON-OFF switch Audio output: FM band connection output Frequency adjustment: press ">" to increase the frequency "<" to decrease the frequency Output voltage: 5 ± 0.1 Vehicle current: ≤600mA Storage temperature: -20 ° C ~ +50 ° C Working temperature: -10 °C ~ +40 °C Stereo resolution: ≥38dB Package List: 1 * User Manual 1 * Charging Cable 1 * Transmitter Note: The hands-free function is not based on the microphone of this transmitter. The transmitter itself does not have a microphone. Plug this transmitter into the phone and use the phone's microphone to make a call. Fast connection and operation, as long as the vehicle frequency and transmitter frequency are the same (do not exclude external strong interference). Please use this product to debug several frequency points and find the most suitable local channel. The channel should not conflict with the local radio frequency. It is best to choose a blank FM channel. The optimal channel is different in different regions. Package List 1 * User Manual 1 * Charging Cable 1 * Transmitter