Car Amplifier Stereo Subwoofer Bass Control Knob Sub Gains Regulator Frequency Controller Line Levels Adjust Features: OOTDTY No power supply design, can be directly inserted and used, no input and output loss, transmission. Two adjustment methods: 1. by gains adjustment, 2. by frequency adjustment. Usage: mainly used to select common output devices and various stereo inputs. If there are two stereo sources (such as stereo, MP3 player, video game, tablet, computer, recorder), the device needs to output to the power amplifier or active speakers. Two sets of stereo source switchers solve the complicated line blocking operating. As long as the required input device source is uniformly to the it can be easily selected. The input and output standard adopts design, and the adopts accurate 2-position manual button Specifications: Material:ABS Voltages: 12V Frequency: 150Hz-40Hz. Gains: 0db to -12db Package Includes: 1Piece Bass Control Knob Note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color of the item. _x000D_ _x000D_ _x000D_