RAM Mount Dual Suction Cup Base w/Medium Length Arm Retention Knob [RAM-B-189B-201-ALA1-KRU]Dual Suction Cup Base with Medium Length Arm & Retention Knob The RAM B 189B 201 ALA1 KRU consists of a double 3. 3" twist lock suction cup base that is connected to the diamond base with 1" rubber ball. The 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 or non porous plastic surface. The ball on this base connects to the standard length double socket arm