Mirror adapters are used to mount universal mirrors on a specific vehicle.
To know which adapter you need, check out these three factors:
Type of thread of the universal mirror: if the mirror ends on a bolt, then we speak of external thread. If your mirror ends on a nut, then we speak of internal thread.
A. Thread diameter of the universal mirror: measure the thread diameter of the mirror and select the correct value for this filter. This corresponds to the "A" side of the adapter.
B. Mirror mount handlebar thread diameter: Measure the thread diameter of the mirror attachment on your handlebars and select the correct value for this filter. This corresponds to the "B" side of the adapter
Yamaha also uses left hand thread for the right hand mirror on the handlebar. So, select 'M8 left' or 'M10 left' at the filter 'B. Handlebar thread diameter'.
New Harley-Davidson models use 5/16" thread on their mirrors, which is almost, but not exactly the same as M8. In some cases a special adapter comes with the mirrors. Please check beforehand if this is the case. Older Harley-Davidson models have mirror stems without thread on the handlebars, instead they use a locking nut. In that case select 'none' at the filter 'B. Handlebar thread diameter'.
Does your motorcycle have no mounting hardware on the handlebars or fairing to accept your mirrors? Then choose one of the clamps from the 'mirror mounting' category.