The RAM .87 X 2.25 W/ 11 MM HOLE AND 1″ BALL marine grade aluminum base consists of a 1″ diameter ball and 2.25″ x 0.875″ base with 11mm hole. This part is often used on motorcycles, attaching to the mirror frame, the main brand of bike for the RAM-B-252U is BMW. This part fits well on many handlebar pinchbolts with a washer (base is 5mm thick).