Power supply: dual DC power supply 58 --- 70V The rated output power: 500W ( 65V power supply, 4 ohm load, distortion 10%) Efficiency: 90% : 90dB The harmonic distortion: 380W ( 65 power 4 ohm speaker, distortion Less than 0.1%) 280W ( 65 power 8 ohm speaker, distortion Less than 0.1%) Frequency range: 20Hz-20KHz Speaker: 4-8 Voltage Magnification: 36 Input sensitivity 1.5V () Output short circuit protection: Yes That output DC protection speaker protection: Yes Over-temperature protection: Yes, radiator FET temperature higher than 100 C, turn off the output Use precautions: Rated supply voltage is 65V, 58---70V range, do not 70V positive and negative do not pick wrong Recommended power supply 65V Recommended 4-8 / 10-18inch speaker Carefully check electricity, the wiring is correct. Material: ABS colour: As shown Package Contents: 1 x Audio Power Amplifier Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.