To suit most bevel twins of the '70s and early '80s, to my knowledge. This newly manufactured cover is fully machined and polished from aluminum BILLET. It's beautiful.
This cover is fashioned after the early, rounder and thinner covers fitted to round-case twins.
The acrylic is held in place via the threaded ring which you can see from the backside. The oil tight seal is made via compression of the O-ring with the threaded aluminum ring, should be no leaks.
I will answer questions promptly, good luck and thanks for looking.