Power Supply: AC DC 6-15V Op Chip: XR1075 Recommended voltage: AC DC 12V Working current: 5mA Tone Adjustment: Treble Bass of high resolution sound enhancement processor xr1075 For listener, this is reason that "" technology can restore true and beautiful sound of scene Treasure. instructions 1. Connect input end to 12V (AC or DC is OK), and connect audio input end to , The output end is connected with rear power amplifier board, and speaker is connected. (as shown in Figure 2 below) 2. The volume, treble output and bass output can be adjusted; from left to right: the first knob is high The second one is bass adjustment, and last one is volume adjustment. Clockwise rotation increases, counter clockwise rotation decreases volume and high and low sound effects. 3. Turn red key to switch sound effect with one key. Different batches may have slight differences in appearance, which not affect use Colour:Red Material:ABS Package Contents: 1 x Audio Preamplifier Only above package content, other products are not included. Note: Light reflection and different displays may cause color of item in picture a little different from real thing. The measurement allowed error is 1-3cm.