The ball base consists of a B size 1" TPU ball, connected to a M10 x 1.25 male threaded steel post TPU over-molded ball joint are anti-slip and wear-resistant for durability and reliability in the most demanding environments The 1'' ball base allows for connection to RAM & BRCOVAN any B size 1 inch ball double socket arm The threaded hole must contain the following dimensions for this base to fit: M10 x 1.25 pitch BRCOVAN 1'' Ball Adapter with M10 x 1.25 x 15 Threaded Post Compatible with RAM Mounts B Size 1 inch Ball Double Socket Arm