i bought one second hand but got no bulb or fitting for it so was wondering where you buy them from

 

I would say that if you have no FITTING for a bulb, it will be difficult to know what sort of bulb to get?
Try the manufacturer/importer first.
If you get no joy there, try a good electronics shop, (Yellow Pages) and if you're still stuck, post again , saying what sort of gauge you have, and maybe someone with the same gauge, or make of gauge, will be able to advise.
alcazar