Crossco PRO Crack Sealer White Elastomeric Fiber Reinforced Crack Filler is flexible styrene butadiene and fiber reinforced brush grade mastic to seal leaks and cover surfaces cracks permanently with or without fiberglass mesh. Excellent to repair expansion and sealing joints in walls, plumbing and electrical outlet. Use interior and exterior. Not crack, sanded, peel or crumble even after being exposed to severe weather conditions. Use on walls and roofs, around pipe and pipeline building, flashing and broken tile. Excellent to repair expansion, joints, deck wall joint, seal plumbing or electrical outlet. Use in concrete, drywall, asphalt, wood and metal.