For use in water features. By expanding to fill gaps and cracks, it works as a water-resistant sealant to help direct the flow or water in waterfall, pond and streamed construction to go where you want it to go, not under or behind rocks. Black to blend in among the stones, rock, masonry, concrete and most other building materials. Safe for fish.Landscape/hardscape foam filler, sealer and adhesive. Damp and dry application. Adheres to stone and rock. Repairs crack and holes in trees. Foam cures in 8 hours. All-direction dispensing. UL classified. One 12 oz can equals up to 19 tubes of caulk.