The ball base consists of a B size 1" TPU ball, connected to a M8 x 1.25 Metric Thread steel post.If you have a M8 hole somewhere this will thread in perfect and give you a reliable mount. Compatible with any motorcycle M8 threaded bolt; ball base allows for connection to any B size RAM double socket arm 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 & FANAUE any B size 1 inch ball double socket arm. ball and socket technology allows for near-infinite adjustability The threaded hole must contain the following dimensions for this base to fit: M8 x 1.25 pitch. Backed by a lifetime warranty FANAUE 1'' Ball Adapter with M8 x 1.25 Metric Thread Compatible with RAM Mounts B Size 1 Inch Ball Double Socket Arm for RAM Mounts Bike Motorcycle Cell Phone Holder Accessories The ball base consists of a B size 1" TPU ball, connected to a M8 x 1.25 Metric Thread steel post. Compatible with any motorcycle M8 threaded bolt; ball base allows for connection to any B size RAM double socket arm 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 & FANAUE any B size 1 inch ball double socket arm. Included B size 1" FANAUE rubber ball allows for connection to any B size RAM double socket arm; ball and socket technology allows for near-infinite adjustability The threaded hole must contain the following dimensions for this base to fit: M8 x 1.25 pitch. Backed by a lifetime warranty