brand new and high quality Features: XH-A105 digital power amplifier board with for high fidelity and two-channel stereo sound quality; input voltage is for DC 12~24V, sound input supports Bluetooth-compatibletooth, TF card, AUX 3.5mm sound line input, can be directly connected to mobile phone, MP3, etc.; power amplifier board It also comes with a volume adjustment function, which rotates the chirp potentiometer clockwise to zoom in and counterclockwise to decrease Bluetooth-compatible operation instructions: When the power amplifier board is connected to the power supply and the Bluetooth-compatible is not connected, the Bluetooth-compatible indicator will flash rapidly. When the Bluetooth-compatible connection is successful, the Bluetooth-compatible indicator will stop flashing. When the song is played, the Bluetooth-compatible indicator will flash slowly. Note: 1. Connect the power input to the DC12-24V power supply. When the power is on, the power indicator will light red and the blue light will flash blue. 2. Connect the sound input to the sound source, such as MP3, mobile phone, computer, TF card, etc. 3. Connect the sound output to the speaker, paying attention to the positive and negative. Bluetooth/TF card volume hole: When the sound input uses Bluetooth-compatible or TF card, you can connect the power cord to the "+ VOL -" three holes to adjust the volume and switch songs. 1. "+" and "VOL" connection: increase the volume 2. "-" and "VOL" connection: reduce the volume About choose sound Input : The Board will Automatic Selection the last sound input .If you use the Bluetooth-compatible Sound input ,and then connect the AUX ,so the board will Automatic choose the AUX Sound input! Amplifier Board only,other accessories demo in the picture is not included. Specification: Product Name: Two-channel Bluetooth-compatible 5.0 power amplifier board Product model: XH-A105 Input voltage: DC12-24V Current: more than 3A Output power: 100W*2 Sound input: Bluetooth-compatibletooth, TF card, AUX Number of channels: two channels Installation aperture: 3MM Installation hole distance: 85x5x78.5MM Material: Metal Size: app.9.2x8.5x1.8cm/3.62x3.35x0.71in Color: As the pictures shown Quantity: 1 Pc Note: 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 Contents: 1 x Amplifier Board