The RAM-B-224-1U is made up of a 3.3 inch twist lock suction cup base connected to the RAM-B-238U; a diamond base with a 1 inch rubber ball. This suction cup is designed to create a super-strong hold on smooth and non-porous surfaces. However, for the best result, mount the cup on a glass surface. Mounting it on a non-porous plastic surface can also be a great option to consider.