Compact Stereo Antenna Harness Adapter for Installing a New Radio Into a Pontiac, Montana SV6, 2005, 2006 Antenna adapter for installing a new Radio into a PONTIAC MONTANA SV6 2005, 2006 CarXtc adapter plugs directly into the antenna wire beyond the radio found in a MONTANA SV6 Plugs directly into your vehicle radio antenna harness behind the factory radio. Antenna adapter is needed for your PONTIAC MONTANA SV6 05, 06 If installing an FM modulator you will need this and the reverse antenna adapter