This ball base consists of a 1" (25.4mm) sized rubber socket ball connected to a 2.43" (61.7mm) x 1.31" (33.3mm) diamond plate. The diamond plate features two holes that measure 1.912" (48.6mm) center to center, matching the industry-standard AMPS hole pattern. This ball base is compatible with a wide variety of RAM device holders and cradles. - AMPS 2-hole pattern - Holds max. 2 lbs / 907 gram normal use or 1 lbs (454 gram) heavy duty use - Marine grade black powder coated aluminum construction with 1" rubber ball