Features: Mono rear amplifier board, if need 2 channel, buy 2pieces. Circuit design use A970/C2240 highly voltages tube 2differential circuit and A1145/C2705 amplification Wide power supply, DC20V-90V can be, as long as the supply of sufficient power Easily reach 200 sound quality, drivingforce plate strong, push 15inch speaker, no pressure Audiophiles, music and other users of the pursuit of highly sound quality. Specifications: Amplifier board size: about 120x60x45MM/4.72x2.36x1.77in Real power: undistorted power 200W Power supply: double-voltages, DC20V-90V20-90V (upgraded version optimised circuitry and part, can be directly on the highly voltages, it is recommend that tuse less than 90V, do not challenge the voltages limit.) Package Includes: 1PCS 200W Power Amplifier Board note: Due to light and screen setting difference, item color may be slightly different from pictures. Please allow slight dimension difference due to different manual measurement.