These are the petrol tank kneepads fitted to swingarm models of mid to late 1950s (but not Featherbed), and also later plunger framed models.
These petrol tank kneepads, as far as I can remember were not never fitted to Norton International's, but were fitted to the slightly more bulbous OHV (ES2, Model 19 etc) petrol tank that came in approximately 1953. They may also have been fitted to the earlier Dominator tanks (not sure on that one?). They were not the type fitted to Featherbed frames though.
Picture of my old 1955 Norton ES2 is included, so you can see the petrol tank these were fitted to. We also manufacture the tank screws to the original pattern.