Aquascape Professional Black Waterfall Foam makes it easy to fill joints and gaps between rocks and boulders, maximizing water flow in streams and waterfalls. Aquascape foam dries fast, lasts long, and the can is specially designed to create an air- and moisture-tight seal for maximum foam yeild and minimal waste. The black polyurethane foam blends easily into rocks and gravel for natural appearance. Ideal for use with Aquascape Professional Foam Gun Applicator.