Product Name: D-Class HIFI Digital Amplifier Board. Product model: RS2092S. Power supply voltage: Dual DC power supply ± 58--- ± 70V. Rated output power: 500W. Efficiency: >=90%. Signal to noise ratio: 90dB. Total harmonic distortion: 380W. Frequency response range: 20Hz-20KHz. Speaker: 4-8 Ω. Voltage amplification factor: 36 times. Input sensitivity 1.5V. Output short circuit protection: Yes. Over temperature protection: Yes.