The RAM-202 marine grade aluminium base consists of a 1.5" diameter rubber ball, connected to a flat 2.5" diameter base. This mount has pre-drilled holes, including the universal AMPS hole pattern.
This component is suitable for higher load applications but must be used with other compatible 1.5" RAM components. It can not be used with the one inch ("B") sized RAM Arms.
See below for the one inch equivalent.