brand new and high quality Features: Stereo audio, it is wide frequency response, high efficiency, low distortion and low noise, the sound effect is good. Designed with a volume potentiometer, you can easily turn the voice high and down. With power supply reverse connection for protection,short-circuit for protection and over-heat for protection. Wide supply voltage and two audio input modes, more efficient. Specification: Material: PCB circuit boards Size: app.55 x 38 x 18cm/21.65 x 14.96 x 7.09in Color: As picture shown Quantity: 1 Pc Product parameters: Product Model: XY-P40W Supply voltage: DC: 8~24V Bluetooth-compatible version 5.0 Connect distance: 15 meters(visible) Output mode: Stereo Output power: 20W x 2 @12V 4 30W x 2 @16V 4 30W x 2 @21V 8 40W x 2 @24V 8 Speaker selected(40W~200W): 4(5-16V supply) 8(5-24V supply) Operating instruction: 1. After connecting the power supply, the blue LED is on, and it goes into Bluetooth-compatible mode, waiting for pairing after playing the Beep; 2. Turn on phone Bluetooth,"XY-P40W"will be searched and display; Click the "XY-P40W",it will connect to the board. It connects successfully with a Beep; 3. After this you can for play the music. The amplifier board will prepare for the next pairing with a Beep. Caution: 1. Keep a safe distance away from router to avoid WIFI interference 2. 5-24VDC is recommended; upper than 26V, it will be damaged. 3. Driving 4 load, power supply must be under 16V; and driving 8 load, supply must be under 24V. 4. The supply current must be 2A at least. 5. The line connecting speaker with module should be within one meter. 6. ESD for protection, please release ESD on your hands before you contact the module. 7. 40W and upper power speakers is recommended. Note: No retail package. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 x Bluetooth-compatible Amplifier Board 1 x User Manuel