The European ceramic style fuses used in all Volvos 1962 to 1993 (except the 700 & 900 series) can sometimes be hard to find. Better auto parts stores will have them, but it’s unlikely that you’d find them at a gas station. We offer these as a convience when ordering other electrical parts.
The fuse panels in these models are known for corrosion problems, which can lead to intermittent electrical failure. A good solution is to clean all the fuse holders with a wire brush & replace all the old fuses with new fuses that have had the contact points coated with dielectric grease. This should provide years of trouble-free service.