Power supply: Dual DC power supply +/- 58-+/- 70V Rated output power: 500W (+/- 65V power supply, 4 ohm load, distortion 10%) Efficiency: equal to 90% : 90dB Frequency range: 20Hz-20KHz Material: CCL Color: blue Total harmonic distortion: 380W (+/- 65 power 4 ohm speaker, distortion less than 0.1%) 280W (+/- 65 power 8 ohm speaker, distortion less than 0.1%) Speaker: 4-8ohm Voltage magnification: 36 times Input sensitivity 1.5V (RMS) Output short circuit protection: Yes Output DC bias protection for speaker protection: Yes Over temperature protection: Yes, heatsink FET temperature higher than 100 Celsius, shut down output Product size: . 100 x 50 x 30mm/3.93in x 1.96in x 1.18in Net weight: .100g/piece Package content: 2 x Digital Amplifier Module Only the above package content, other products are not included. Note: Light 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.