Connect any B size RAM double socket arm with the RAM® Double Ball Adapter with Round Base with two B size 1” RAM rubber balls. KEY FEATURES 2.5" round plate connects to RAM® device holders containing the universal AMPS hole pattern Two B size 1" RAM® rubber balls allow for connection to any B size RAM® double socket arm; ball and socket technology allows for near-infinite adjustability Made of powder-coated, marine-grade aluminum for durability and reliability in the most demanding environments The Double Ball Adapter with Rounder Base consists of two 1" diameter rubber balls connected to a post and 2.5" diameter round base. The round base has pre-drilled holes, including the universal AMPs hole pattern and 3-hole 120-degree pattern. The 1" balls measure center to center 2.5" apart.