An adjustable 4 channel original amplifier retention interface. This part is for fitting an aftermarket radio to a car with an original fully amplified sound system including cars with BOSE, Harman Kardon or car manufacturer specific premium sound systems. Suitable for cars which take a low level (non-amplified) audio output from the original radio which is then amplified by the original amplifier.

The ISO to ISO wiring design allow the interface to be fitted between an aftermarket radio and a car specific ISO cable or steering wheel control interface.

The adjustable gain controls on each of the 4 channels allows fine tuning for the optimum sound quality, including tuning out external noise and volume control. The interface has a buitl in ground loop isolator and filters to get the best sound from the original amplifier.

Suitable for a number of cars with a premium sound systems, including BOSE and Harmon Kardon.