Prime Lock Plus Primer/Sealer/Stain Blocker is a high hiding, alkyd resin based, primer-sealer-stain blocker for interior use and spot priming exterior surfaces. Excellent for priming over plaster, drywall, wood and previously painted or varnished surfaces. It can be top coated with any oil or latex paint. It provides excellent enamel holdout and will not raise wood grain. Use it as a primer prior to applying most wall coverings. It has excellent adhesion over glossy surfaces. It is effective for “bleed through” from fire and smoke damage, water stains, wood tannin, crayon, lipstick, ballpoint pen and felt pad inks. Severe water stains may require an additional coat of Prime Lock Plus before applying the finish coat. Pine knots should be spot primed with pure shellac prior to priming with Prime Lock Plus.