Tube: 6j3(The tube is disassembled) Power supply: DC12-16V, current 1A or more (DC12V 1.5A supply power is recommended) Power socket: DC3.5/5.5*21 Product support replace tube: 6J1 6J2 6J3 6J4 6J5 6A2 6K4 6K5 6AK5 6AU6 6BA6 6BD6 EF93 6K7 GE5654 etc. Pre-stage magnification: voltage magnification 5 times Pre-stage frequency response: 5HZ-500KHZ Pre-level sensitivity: 3V Audio input: low-level signal input such as mobile phone, CD, computer, TV, MP3, etc. Audio output: connect to power amplifier or active speakers Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Color: random color, don't accept the specified color. Material: plastic Package Contents: 1 * Audio Amplifier Only the above package content, other products are not included. Note: Light reflection 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.