Stereo Antenna Harness Adapter for Installing a New Radio Into a GMC, Sierra, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Antenna adapter for installing a new Radio into a GMC SIERRA 2007, 2008, 2009, 2010, 2011, 2012, 2013 CarXtc antenna adapter plugs directly into the factory radio pulled from a SIERRA. Has a male Motorola plug on one end and OEM jack on the other - Use with New Aftermarket Radio Installs - Keeps FM / AM Factory Antenna Useable. Antenna adapter is needed for your GMC SIERRA 07, 08, 09, 10, 11, 12, 13 If installing an FM modulator you will need this and the standard aftermarket antenna adapter