The RAM-B-202-G1U RAM marine grade aluminum base contains a 1" diameter rubber ball connected to a flat 2.5" diameter base. This mount has pre-drilled holes, including the universal AMPS hole pattern. The connection hardware, which will connect to many different cradle types including, and not limited to, the following cradles and mounts MADE BY GARMIN:
1" Rubber "B" Ball Size
The "U" in the part number reflects product packaged in poly bag.