Looking at buying a new style petrol cap for my car.
Don't really want one that fits over the one that I already have, like that hideous Aston, the grub screw thingy, nor do I want a Monza style with the fiddly brass ring fitment so am after some thing else .......however.....what measurements am I looking at as al the ones I have seen seem to quote internal sizes ranging from 37mm to above 50mm, my car is being worked on at present so don't have it handy to measure..........help apprciated.