Operating voltage: Recommended AC double AC22-26V Output peak: 250W + 250W Output load: 4-8 ohm Output impedance: 30K ohm Color: green material: metal Total harmonic distortion: less than 0.02% Frequency response: 10HZ-20HZ Signal to noise ratio: 90db Weight : 473g Power amplifier tube model: 2sk385 Size : 15.8 x16.7 x 4.2 cm Using high-power output tube to do after-level drive, with a variety of speakers, the output power, the latest PCB software design, to ensure that the circuit is stable and improve signal-to-noise ratio. Application of digital delay reverberation, and with tone control, easy to install. Package: 1pcs Audio amplifier board Only the above package content, other products are not included. Note: Light shooting 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.