This is the distinctive(and now very difficult to find) conical shaped press steel wheel bearing dust cover that was commonly fitted to 'cotton reel' type hubs - i.e. pre plunger (i.e rigid frame) rear hubs and those front hubs that had the 'bolt on' brake drum to the cotton reel hub - used on all Norton models in the 1930's, WD models and some hubs in 40's/50's - it being slightly conical in shape.
The accompanying photo shows one of these bearing covers fitted over a 1930's 'Cotton reel' type hub - easily identifiable from the plunger type rear wheel, by having 3 holes for the drum securing bolts
As with the other 'flat' type we also produce, these are identical in shape and size to an original (as always - a NOS original was used as a pattern), except that rather than being in dull nickel plated steel, these are manufactured in stainless steel, then lightly blasted to give them the original satin finish.
However, if you like them in the natural semi-polished stainless steel finish, these are available too. These are now a very hard to find item in good condition, as whenever you find them at autojumbles - invariably they will have one of the tags broken off!