The RAM-B-272U consists of a 1″ diameter ball and base with 9mm hole. This part is often used on motorcycles, attaching to the mirror frame, the main brand of bike for the RAM-B-272U is BMW.Ball1″UPC793442102721MPNRAM-B-272ULNS Part #170-RAMB272UKMS Part #RAM RAMB272UDMP Part #38-1926