2-to-4 channel adapter for standard / radio only wiring

Exactly equivalent to BMW part number 65-12-1-379-329. 

Plugs into fader connector of a 2 channel standard / radio-only audio system. With this adapter you can run an OEM 4 channel radio like the CM5908 or KE83-ZBM without a trunk amplifier in a car with 2 channel radio-only wiring.

Also compatible with Amp+ if your car has 2 channel standard / radio only wiring.