Features Designed with LED indicators to monitor the power status in real time. IC bracket can be soldered at any time to feel the effect of different op amps and improve playability. The adjustment potentiometer is fully sealed type, and the input and output ends are made of pure copper terminals. Wiring is very convenient. This card has strong anti-interference ability. There is almost no noise near the horn when there is no signal input. The board is simple and beautiful in design, and the wiring is reasonable, which gives the board a very high signal-to-noise ratio. Specification: Condition: 100% Brand New Supply voltage: DC10-24V DC single power supply. Frequency range: 22Hz-300Hz Audio Input: Mono or Dual Channel Audio output: Mono Circuit board standard: approx. 78 x 32 mm/3.1 x 1.3 inches, thickness: 1.6 mm PCB Material: FR-4 Super Hardness Fiberglass Board Plate fixing hole center spacing: 70 x 24 mm, hole diameter: 3.2 mm. Potentiometer shaft spacing: 32.5 mm Weight: approx. 32 g/1.1 oz. Package list: 1 x Filter Panel 2 x Screws 2 x Gaskets 2 x Button Cap Note: This card is a heavy bass preamp card. It will not ring when directly connected to the horn. It must be connected to a pure final stage power amplifier board to create an active subwoofer. The power of the pure final stage power amplifier board is selected according to the shock level of individual needs. The higher the power of the pure final stage amplifier, the more shocking the bass effect will be. The so-called low-pass filter card filters the high parts above the human voice and retains the low frequency part to zoom in order to improve the playback strength of the bass, and does not hear human voices and high-frequency instrument sounds during playback. Package List