This one has an overall rubber boot which means on some vehicles (mine is a very late S2A hardtop), it will not fit into the hole as is. The originals (55 years old) only had a rubber gasket. The trick is to carefully cut the boot part off with a Stanley knife leaving the rubber gasket shape just like the originals. The boot fits into the bigger holes in the open truck back as far as I can tell as these had a bigger hole. The mounting screws clamp this to the vehicle producing a good seal. As an aside, I also replaced the lens mounting screws with stainless steel equivalents costing just pennies - worth it in the medium to long run. I also replaced the supplied filament bulb with an LED one, but as the bulb mounting is actually metal, this is optional as it can take the heat of the filament bulb.
