SOUND MAGUS HTL8 4 Channel Line Level Adapter Switchable from 2 to 4 Channel Professional Car Stereo Speaker Level to RCA Converter Easy to install || The Sound Magus HTL8 is a 4-channel line level adapter that's switchable from 2 to 4 channels. It's designed to convert car stereo speaker outputs to RCA outputs, allowing the addition of amplifiers and subwoofers to factory systems without RCA outputs. || || Converts car stereo speaker outputs to RCA outputs; Allows the addition of 4 channel amplifiers to most stereos without RCA output; Allows the addition of amplifier and subwoofer to existing factory system; For car stereo up to 90 watts; Easy to install; Creates a remote out signal for your amplifier turn on trigger || || If you're running an external amp using the audio feed from your rear speakers then you will be getting the full range of frequencies through your subs. An after-market head-unit with an RCA output, or some amps, will have a x-over built in that can be set to only allow bass frequencies through. If your amp doesn't have one and you don't want the subs to sound awful with your car's stock system, an external x-over block is what you need. || || Key Features (1) || Channel Conversion : Switchable from 2 to 4 channels || Speaker to RCA Conversion : Converts car stereo speaker outputs to RCA outputs || Remote Output : Creates a remote out signal for amplifier turn-on trigger || || Key Features (2) || Easy Installation : Simple setup for most car stereo systems || Compatibility : Works with car stereos up to 90 watts