The front gallbladder rear stone power amplifier module supports the replacement of a variety of electronic tubes, Bluetooth 5.0 + aux input. The electronic tube of this product can be replaced and supports a variety of small 7-pin electronic tubes such as 6j1, 6m 1, 6j2, 6m 2, ef95, 6ak5, ge5725w, ge5654w, etc. Rotate the switch/volume knob to adjust the volume to an appropriate level. Enjoy the charm of tube amplifiers quietly. Turn the switch/volume knob to turn on, and the indicator light flashes. This product has two audio input modes: AUX wired and Bluetooth wireless. AUX wired input is preferred. Choose the audio input method you want. Install the randomly worn electron tube into the electron tube holder according to the direction (the electron tube is not divided into left and right, check whether the pin is deformed before installation, if there is any deformation, you can gently correct it with your hands, and slowly insert the electron tube vertically into the electron tube holder during installation. (Be careful not to shake as much as possible) Adaptive power supply: DC12V; 3A Audio input: aux + Bluetooth Input sensitivity: 800mv Adaptive horn: 4-8 5-50w Power output: Max 30W* 2@4 Frequency response range: 20Hz-20KHz Bare metal size: 107 x 80 x 39mm (height excluding electronic tube) Plug Type: US Plug, it applies to Canada, India, Mexico, Thailand, Taiwan, the United States, the Philippines and so on. Colour: black Material: PCB Package Contents: 1 * Electron Tube Amplifier Module 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.