①. Can play MP3 format music from U disk and SD/MMC card directly, support FM stereo radio, selected four-channel power amplifier integrated circuits, minimal distortion but strong power, input and operational amplifier IC for circuit design, parent and bright sound. ②. Filtering and anti-large-capacity power circuit, four DSP sound field patterns, two main channels and two surround channel output, input voltage: DC 12V, frequency response: 20Hz - 20KHz. ③. Harmonic distortion: 0.05% and less (4W 1KHz), SNR: 85dB, high control: 12dB, bass control: 12dB. ④. Signal level: 220MV 47K, FM frequency response: 87.5 - 108MHz, power: 20W x 2. ⑤. Color: red. ⑥. Material: aluminum alloy. ⑦. Product size: 15.5 x 8.5 x 4cm. ⑧. Package Contents: 1 x HY - 400 Power Amplifier, 1 x Remote Control, 1 x English User Manual. Only the above package content, other products are not included. ⑨. 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.