ITEM NAME:TDA7850 4 Channel Car Power Amplifier Board with BA3121 Noise Reduction Product Description Description: Features: 1. With BA3121 isolation noise reduction (to eliminate common ground noise). 2. The circuit design is reasonable, no popping sound at startup, no need to connect the speaker protection board. 3. 4 channel input / 4 channel outputs. 4. DC 12V power supply or use 12V car power supply. 5. There is no delay function without delay function, no need to install speaker protection. Specifications: Product size: 65mm*52mm*40mm/2.56*2.05*1.58" Package weight: 57g Notes: 1. Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! 2. Please allow 1-3cm measuring deviation due to manual measurement. Included: 1 XÂ TDA7850 4 Channel Car Power Amplifier Board.With BA3121 isolation noise reduction (to eliminate common ground noise). Included: 1 X TDA7850 4 Channel Car Power Amplifier Board. The circuit design is reasonable, no popping sound at startup, no need to connect the speaker protection board.