Features and Benefits: 77451 2K Quicksand Urethane Primer is a fast drying, high build primer with excellent color holdout. 77451 offers superior adhesion, easy sanding, and can be topcoated with any paint system. Designed to be applied to steel, aluminum, iron, fiberglass and2K urethane primer/surfacer | High build formula | Superior adhesion and color holdout | Easy sanding | Ideal for use on prepared steel, aluminum, iron, fiberglass and painted surfaces | 4:1 mix ratio | Color: buff | Size: gallon