The RAM-B-238U ball base consists of a 1" B size rubber ball connected to a 2.
The RAM-B-238U ball base consists of a 1" B size rubber ball connected to a 2.43" x 1.31" diamond plate. The diamond plate features two holes that measure 1.912" from center to center, matching the industry-standard AMPS hole pattern. This diamond ball base is compatible with a wide variety of RAM® device holders and cradles.