These are the girder fork rubber 'bump stops' as fitted to many Norton models where girder forks were used - to help prevent bottoming out over heavy bumps. Price is per pair
As can be seen from the photograph - if you have the cast 'Bump Stop' holders fitted to your girder fork blades - then these are the correct rubbers to fit those castings. The castings can be adusted on the rear girder fork leg on either side, so that when you go over rough bumps and the main spring 'bottoms out', then the nuts on the rear lower fork spindle hit against these hard rubber stops.
These are even more useful if your original main girder fork spring is getting tired - as so many now are. I believe these were original fitting on Norton WD 16H/Big4 models (see period photograph), but are a very popular mod on earlier girder fork models.
We have these manufactured for us to the original pattern - as can be seen from the photograph, the tired looking rubber on the right is an original that had been fitted to a working Norton, with our re-manufactured rubbers fitted into the original casting that rubber had come from. They are to original dimensions and of very hard wearing neoprene rubber, so should last for years.
Note: a very similar rubber was also fitted to some Velocette models, these can also be fitted as an alternative to those Velocette models.
As a final point, I have been asked in the past if we can provide the actual bump stop rubber castings. If enough interest I will continue with this (it has been a back burner project with one of our casting companies). Likewise, I was intending to reproduce the casting bolts and nuts in stainless steel - for both, if you are interested, please let us know on our normal email: firstname.lastname@example.org