A very fast drying single component primer filler providing good adhesion onto bare metal as well as protection against corrosion and provides a good smooth non-porous high build finish. ProXL Premium 1pk HS Primer Filler has excellent coverage and filling properties which is also easy to sand, both wet and dry (from 400 grit). It can be over coated with almost any topcoat (water based or solvent based) after just 30 minutes.