511 Porous Plus is a penetrating sealer designed for the protection of the most porous surfaces. 511 Porous Plus forms an invisible barrier that is resistant to moisture and stains while allowing vapor to escape. 511 Porous Plus is not a surface coating and will not alter the natural look. All surfaces are harder and less slippery. WATER, STAIN & SLIP PROTECTION FOR: Sanded Grout, Terra Cotta, Cantera/Adoquin, Polished Marble, Polished Granite, Limestone, Sandstone, Slate, Saltillo Tile, Flagstone, Flamed & Honed Granite, Honed/Textured Marble. SPECIAL FEATURES: Interior & Exterior Use Weather Resistant. OK for Food Areas. Superior Coverage. Easy to Use. U.V. Transparent.