This is an alkyd based enamel primer for use on ferrous metal. It provides a heavy duty hard enamel finish that stops moisture from reaching the metal, and thus, preventing rust. It is resistant to abrasion, and corrosion. For maximum durability, requires a high quality, rust preventative top coat. Is also mold, and mildew resistant. 1 Gallon container $80+taxes. In store purchase only, unless on account.