This is a two-channel, audio input, 10-LED-per-channel Sound Level Meter Kit. It uses two LM3914s that will accept an RCA input. The audio source can come from just about anywhere. Each channel has two adjustment controls, one for the input Op Amp gain and the other for the LM3914 range. Maximum audio input voltage should not exceed 5v. Kit can run off of 9 to 12 volts dc. Kit will include the PCB, all components, and schematic to complete the kit. You will need standard soldering equipment. It is 3.25" x 3.25" with 4mounting holes.NightFire Electronics