1. On-board TDA2030A audio power amplifier chip. 2. Mono 18 w power amplifier circuit design. 3. On-board speaker terminal block 4 On-board 10k adjustable resistance, can adjust the volume of the amplification. 5. On-board power light. 6. Chip has lead to the main pin, can directly input audio signal. 7. Working voltage: 6 -12 v. 8. Board size: 31.6 (mm) x23.2 (mm).