Rust-Oleum LeakSeal Flexible Rubber Sealant (450g) is an easy-to-apply, paintable sealant that provides a durable, water-tight seal for leaks and cracks. Ideal for use on gutters, roofs, flashing, ductwork, PVC, masonry, concrete, and more, it dries to a semi-smooth, firm finish that won't sag or drip. This flexible rubber sealant can be top-coated with latex or oil-based paints, making it perfect for a variety of surfaces. For best results, apply outdoors for optimal spray coverage and performance.