They are rated at 9 lb load per mount used

They have a ribbed rubber flange that measures about 1-5/8" across the opening

check out How to Mount a Motorcycle Fender - Part 1 from back in 2010

standard for tapered threads used on threaded pipes and fittings

#8303 CAD Complete Stock Hardware Kit - 1958-1965 Harley-Davidson Panhead - CAD Plated Colony_Special_Order They are rated at 9Complete stock hardware kit for Harley Davidson Panheads 1958 1965, CAD plated. Each kit contains all the stock motor nuts, bolts, washers and studs for your motor. The kit includes primary cover screws, lifter base screws, circuit breaker screws, case studs and nuts, timing plug, cam cover screws, cylinder base nuts and washers, oil pump nuts and bolts, transmission side cover nuts and washers, transmission top screws, transmission fill plug,