The ball base consists of a B size 1" ball, connected to a M10 x 1.25 male threaded steel post TPU over-molding ball joint, wear-resistant and anti-slip, for durability and reliability in the most demanding environments The 1'' ball base allows for connection to RAM & BRCOVAN any B size double socket arm The threaded hole must contain the following dimensions for this base to fit: M10 1.25 pitch with a 14.5mm flange diameter with a 10.15mm thread length 1'' Ball Adapter with M10x1.25 Threaded Post Suitable for RAM Mounts B Size Double Socket Arm