The CI 420-1 is a stand-alone XM approved antenna that operates with Garmin, Avidyne, Heads Up Technologies, and WeatherWorx weather data systems in the popular teardrop shape. This same antenna will also operate popular XM based music systems. This antenna has been tested under the most rigorous conditions as outlined by RTCA DO-160D. Matches footprint of Garmins GA56, Honeywells KA92 and Comants CI 405 Series. This unit is PMA'd.