MOLD ARMOR 100% Silicone Mold Free Caulk & Sealant (White) works on indoor hard surfaces such as glass, granite, marble, wood, ceramic, metal, aluminum, fiberglass, and painted surfaces. The flexible, crack-proof formula is made of silicone and has excellent adhesion. This chemically curing sealant is both mold and mildew free and works for the shower, tub, kitchen and countertop. To use, remove any caulk, dirt, grease or soap residue from the desired surface. If mold is present, use a mold and mildew cleaner such as Mold Armor Mold & Mildew Killer & Quick Stain Remover to kill any mold on the surface. Once dry, surface is ready for application. Packaged in a 5.5-oz. tube. Keep out of reach of children.