An essential part of every backyard water feature, the Aquascape Pond And Waterfall Foam Sealant is a professional grade product designed to fill the joints and gaps between rocks and boulders, allowing for optimal flow in streams and waterfalls. The black, expanding polyurethane foam provides a natural appearance that seamlessly blends into the rocks, and doesn't detract from the appearance of your pond or waterfall. The easy to use spray can is well suited to quick, convenient touch ups and is completely pet safe. Comes in a 12 ounce container.