Rust-Oleum High Performance 15 oz. LeakSeal Black Flexible Rubber Coating is a rubberized protective utility coating used to fill and seal leaks and cracks. Easy to use spray provides a watertight, flexible seal to prevent moisture penetration, rust and corrosion on gutters, roofs, flashing, duct work ,PVC, masonry and more. LeakSeal dries to a semi-smooth, firm finish that will not sag or drip and can be topcoated with water-based or oil-based paint after 24 hours.