Description Product Function: Divert water over rocks, instead of around and under them by expanding and sealing gaps between rocks and pond liner. Water is known to take the path of least resistance. It easily flows under waterfall rocks, reducing the appearance of your waterfall feature, Pur Black NF Gun Foam can block these paths and simplify waterfall construction allowing you to enjoy the full benefit of your waterfall. Once dry, excess foam can easily be removed and will look like shadows between rocks. *Applicator gun sold separately
