As Seen on TV! The easy way to coat, seal & protect. Flex Seal liquid rubber sealant coating is excellent for roof leaks, butters, skylights, hoses, windowsills, PVC pipes, flashings, duct work, foundations, basements, chimneys, downspouts, vent pipes, A/C drip pans, RV's & Campers, trailers and so much more! Flex Seal is a rubberized leak sealer that seeps into cracks and holes to seal out air and moisture. Flex Seal is a long-lasting, watertight, paintable, flexible rubber coating that won't sag, drip, crack or pell. One can of flex seal treats 2 to 12 square feet.