Prosoco Sure Klean Weather Seal Blok-Guard Graffiti Control II is a water-based graffiti and water repellent for porous masonry. Sure Klean Weather Seal Blok-Guard Graffiti Control II is a clear-drying, water-based silicone emulsion for weatherproofing concrete block and other porous masonry materials. Blok-Guard Graffiti Control II protects interior and exterior masonry surfaces from graffiti attacks without altering the natural appearance. Blok-Guard & Graffiti Control II also protects exterior walls exposed to normal weathering. Blok-Guard & Graffiti Control II is easy to apply with low-pressure spray, brush or roller. Treated surfaces resist penetration of most types of graffiti.