Unlike mortar or cement, Black Waterfall Foam expands to fill voids between the BioFalls, rocks and liner, diverting water over the top of stones. Additionally the Foam will not crack in freezing climates like mortar can. Black Foam looks like a darker part of the stone, a corner or shadow. Fish and Plant Safe. 12 Fl oz. can. Cannot ship Next Day Air or 2nd Day Air DOITBLACKFOAM Most Orders Shipped Out Same Day! Premier Ponds LLC pondinfo@premierponds.com U.S.A. Copyright © 1999 - 2007 Premier Ponds LLC, North Salem, New York. All rights reserved. Thermo-Pond Heater 3.0, Aquascape Designs Pond Kits, ScareCrow Sprinkler, Nursery Pro Micro Pond Kits, AquaClearer, Microbe-Lift, Great Blue Heron Decoy, Pond Liners, Thermo Pond Heater & Deicer, Premium Koi Food, Select Koi, Butterfly Koi, Pond Aeration Pumps, Flexible PVC Piping, BioFalls, Skimmer, Aquascape Pumps, Cat Stop!, Animal Control Products, Pond Netting.