For a smart solution to your most stubborn gaps, The Beckett 12-ounce Black Waterfall Foam Sealant helps to seal your rocks and coping stones while keeping them firmly in place to direct waterflow over rocks instead of under them. For a waterfall that's both beautiful and efficient, throw on some gloves and get to sealing! Easy to use and non-toxic, this foam appears black in color when discharged. In the following hours, foam will expand up to 3 times its size to fully fill the gaps in the rock structure, as well as change colors and begin to blend into the surrounding environment. Foam will cure in approximately 1 hour, and will be ready for water flow within 8 hours of application. This product comes with an easy-to-use dispenser tube, making application a breeze for anyone! While this sealant is non-toxic and safe to use, it is highly recommended to use gloves while applying to avoid getting the sticky substance all over your hands. This sealant is great for do-it-yourself work that isn't just limited to landscaping- use it to fix a wobbly showerhead, protect breakables in packages, improve the sturdiness of a sink or tub, fill gaps in walls and insulation, or for any other home project that you think needs some more stability. The Beckett Waterfall Foam Sealant is the perfect tool to have on hand for your every sealing and insulation need.