#190 Perfik-Cover Quick Dry Oil Base Undercoater is a premium interior/exterior primer that offers excellent hiding, sealing, stain blocking and mildew resistance in an oil-based coating. This, high solids, full bodied product is designed to penetrate surfaces and exhibits excellent flexibility, adhesion, sealing and stain blocking. Being an oil-based product, #190 has excellent adhesion to existing alkyd enamels with less surface preparation. This product is recommended for exterior use on all types of dimensionally stable wood and ferrous metal surfaces. #190 is the product of choice for priming bleeding woods such as cedar or redwood to stop the tannin bleed through. This product is not recommended for aluminum, galvanized metals, exterior pressure treated pine or masonry surfaces. Some knotholes may require shellac to stop the tannin bleed through.