When you decide to install an aftermarket product that requires an antenna signal in recent GM, Ford, Jeep, & Chrysler vehicles, an antenna adapter is required. The antenna adapter is a small jumper cable usually less than 6 inches in length is needed to convert the factory unique antenna terminal (car side) to standard Motorola (DIN) connector found on most aftermarket products (e. g. Radios, FM Modulators etc. ) requiring an antenna signal.