Rust-Oleum 275117/RST275117 Brush Black LeakSeal Rust-oleum LeakSeal Brush is an easy to use, rubberized protective utility coating designed to fill and seal leaks and cracks It provides a water-tight, flexible seal that prevents moisture penetration, rust and corrosion Great for gutters, roofs, flashing, ductwork, PVC, masonry, concrete and more