These Adaptors Allow You to Install an Aftermarket Amplifier to Your Factory Head Unit These devices take the speaker level outputs from the head unit and reduce the signal to a level of which an aftermarket amplifier can use without overloading its inputs. Aerpro Line Output Converters will convert your existing cars factory head-units high level (speaker output) into a low voltage line level (RCA) output allowing you to add on an aftermarket amplifier to an OEM headunit. Aerpro AP3044A Features: Remote output trigger LED power indicator Eliminates signal noise Audio ground Individual channel gains Adjustable 6:1 stepdown gain Aerpro AP3044A Specifications: Number of input channels: 4 Number of output channels: 4 Auxillary power required: Yes Maximum DC input voltage: 16V Maximum RCA output voltage: N/A Maximum high-level input: 80W Colour: black Dimensions: 113W x 91D x 30H Inclusions: 12-pin connector block, mounting screws