Crown Trade Fastflow Quick Dry Primer Undercoat White 2.5L is a high-performing, water-based undercoat that provides excellent adhesion and opacity. Its rapid-drying properties make it ideal for use on interior and exterior woodwork, metals and building plastics to prepare them for the final finish. This quick-drying primer undercoat is specially formulated to resist peeling, blistering, flaking, and discolouration for a long-lasting, durable finish.