PT-573 Filler/ Sanding Epoxy Primer is a two component epoxy based primer. PT-573 is capable of filling small holes and imperfections before top coating. PT-573 provides a smooth, sandable base coat that improves the adhesion and appearance of the top coat. Because of PT-573’s unique formula, this primer also provides excellent rust and corrosion protection. This sandable primer is compatible with PTI’s epoxy (PT-426F series) and Polyurethane (PT-785 and PT-799 series) top coats.