This is a multifunctional high-fidelity stereo audio decoding transmitter that integrates Bluetooth audio decoding, U disk music file decoding, computer USB sound card, AUX, FM transmission, and AM signal modulation transmission. This board uses a 0.96-inch OLED display to display the playback status and related information. When playing U disk in USB music mode, it supports decoding file formats MP3/WAV/WMA/FLAC/APE. In Bluetooth mode, it supports /AAC audio transmission protocol, and in AUX mode, it supports stereo line audio input. In USB sound card mode, you can directly use the USB cable to plug into the USB port of the computer as a sound card to obtain better audio digital signals. The microphone input can only be input in AUX mode, and it can be used for more expansion. The panel of this product is made of aluminum alloy. Power supply: DC12V FM transmission distance: more than 2000 meters tested with car radio, more than 500 meters tested with ordinary radio. Transmission frequency 76MHZ-108MHZ AM signal: First, in order to obtain a relatively high-quality and clear sound, a sine wave signal is used for modulation, which is clear and smooth. It is first output as a modulation signal. Within the actual distance of 3 meters, the signal is relatively clear and clean, which is the quality of some radio stations. It can be used as a modulation signal and test, and the actual transmission distance is small. Modulation frequency: 0.1HZ-12MHZ Note: 1. When using the GP transmitting antenna, be sure to use a feeder to connect the antenna rack to the transmitter. 2. Do not use the telescopic antenna on the GP antenna to directly connect the transmitter. Plug Type:EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on. Voltage:AC100-240V Color:White Material:Aluminum Alloy Package Contents: 1 * AM Transmitter 1 * GP antenna 1 * feeder 1 * power adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.