This is a TRE4623 2-N-1 Red Oxide Primer. 2-N-1 primers are a specialty coating for easy & convienent priming of metal & plastic parts. These primers help prevent rust & seal-out moisture while providing a smooth base for topcoat application on metal substrates. 2-N-1 primers also have excellent flexibility & adhesion properties that enable them to be applied to flexible & rigid parts. Is also fast drying, provides superior fill & build, and are easy to sand. THey are compatible with virtually all automotive paints.