This is a level controller for stereo input with RCA pin input/output. It is brand new and unused. Since it does not have a power supply, it cannot increase the level. It is useful for adjusting the level of a subwoofer or for level control when the audio volume is different. The pin cable length is approximately 20cm. The main body is 4cm wide, 3cm deep, and 2cm high. The case is plastic.