Ram Mounts Suction Cup With Twist Lock. The 3.3" diameter suction cup is designed to have an extra strong hold on any smooth non-porous surface but for best result mount the suction cup on a glass surface. The diamond shaped end has two holes 1.912" from center to center. This will connect to RAM-B-238 Diamond Plates Series the universal industry standard AMPS hole pattern or directly to the back of the RAM Composite HOL Cradles. This suction base DOES NOT have a RAM 1" rubber connection ball. Material: High Strength Composite Ball Size: 1" Rubber Ball "B" Size Features of Ram Mounts RAP-224-1 Suction Cup With Twist Lock 1" ball 2.43" x 1.31" diamond base Base has two holes 1.912" from center to center Package Contents: Ram Mounts RAP-224-1 Suction Cup With Twist Lock Ram Mounts RAP-224-1: Suction Cup With Twist Lock