RAM Mount 1.5" Ball "Rugged Use" Mount f/Garmin echo 200, 500c, & 550c [RAP-101U-G4]1. 5" Ball "Rugged Use" Mount f Garmin echo 200, 500c, & 550c The 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