The RAM-B-101-G2U consists of a double socket arm and two 2.5" diameter round bases with the universal AMPS hole pattern. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at both ends of the double socket arm. With a twist of the arm knob you can move the RAM-B-101-G2U mount to your optimum viewing position.UNPKD Ram Mount - Garmin 4xx and 5xx SeriesColor: Black Powder CoatBall Size: 1 Inch Rubber BallMaterial: Powder Coated Marine Grade Aluminum Product : RAM MOUNT DOUBLE SOCKET ARM F/ GARMIN FIXED MOUNT GPS 1" Manufacturer : RAM MOUNT Manufacturer Part No : RAM-B-101-G2U UPC : 793442000836