This is a TRE6404 Gray Urethane Primer. EZ Sand Acrylic Urethane Primer is a premium grade lead & chromate-free two component primer surfacer. It provides exceptional fill & build characteristics providing a base that yields excellent topcoat hold out, gloss & DOI. This primer sands easily wet & dry & can be directly topcoated with alkyd enamels, acrylic enamels, lacquers & basecoat/clearcoat systems.