Zinsser B-I-N is a three-in-one shellac-based primer, sealer and stain killer for use on interior surfaces and spot priming on exterior surfaces. It can be used on interior ceilings, doors, walls and furniture, and for spot priming on exterior metal, trims, PVC and wood. It offers great adhesion to glossy surfaces, including glass, with no need for scuff sanding. It also blocks stubborn and persistent stains, including those left behind by water stains, fungal degradation, nicotine, oil stains and marker pens.