1.5″ Ball “Rugged Use” Mount f/Garmin echo 200, 500c, & 550cThe RAP-101U-G4 consists of a 2.5″ diameter round base with the universal AMPS hole pattern, double socket arm and round adapter base that attaches directly to the back of the Garmin echo. Designed into the mount is a 1.5″ diameter patented rubber ball and socket system with adjustment points at both socket ends of the arm; this with RAM’s rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles. Included is hardware that is used to attach the Garmin echo to the RAM Mount.Material: High Strength Composite Ball Size: 1.5″ Rubber Ball Size Note: The “U” in the part number reflects product packaged in poly bag.