Features: 1. This is a 5V speaker decode board with amplifier, directly connected to the speaker, with Bluetooth and memory card function. 2. LIN adjustable to control external audio input volume and mute. 3. The potential of the panel is dual-purpose for power switch and volume adjustment. 4. 4 buttons, 10W amplifier (2*5W) with AUX, FM, USB, SD and Bluetooth. 5. Support for Bluetooth4.0EDR. 6. Support USB/SD/Bluetooth/FM/LINE automatic switching. 7. Support MP3/WMA/WAV/FLAC format music. 8. Support USB, SD, MMC card for playing. 9. Support USB/SD card switching, previous song, next song, fast forward, fast reverse, knob volume adjustment. 10. Support FAT16, FAT32 file system. 11. Supports songs of MP1 Layer3, MP2 Layer3, and MP3 Layer3 versions. 12. Support power-off memory function: remember the song and volume played before power-off. Specification: Material: ABS Color: Silver Working voltage: DC5V 5V (the 3.7V-5V is connected to the back of the board. If the 3.7V lithium battery is used, the 3.5DC5V hole of the panel is the input of charging) Working current: 800MA-1.2A Output amplitude: 10W (connected to two 4 ohm 5W full-range speakers) Panel size: 135 * 73 * 45 MM Opening size: 117 * 54 * 45 MM Size: 135 * 73 * 45mm / 5.3 * 2.9 * 1.8in Weight: approx. 93g Package List: 1 * Decode Board Panel button description: 1. "PREV/VOL-": Use a potentiometer with a switch; 2. "PLAY/PAUSE": In the USB/SD/Bluetooth state, short press play/pause; in the FM state, long press the full channel search station and save the station. 3. "Upper/Slow": When USB/SD playing status, press and hold for fast forward and fast reverse; in Bluetooth state, short press for up/down track; in FM state, short press up/down for Radio station. 4. "MODE": USB-SD-Bluetooth-FM-AUX Switch 5. 3.5 DC5V input (3.7V lithium battery is connected to the rear of the board, and the 3.5DC5V hole of the panel is the input of charging) 6. 3.5 AUX for audio input Note: 1. If it is not a smartphone (Android), enter the password 0000. 2. If the input voltage of this decoder board is too high, it will be damaged. If the voltage is too low, it will not work properly. Be careful not to connect the wrong "+" and "-" poles; please pay attention to the voltage and current values. 3. The Bluetooth device name of this product is YMX-188BT or YMX-189BT.