Product description: Leakmaster Hydrophilic Gun Grade Polyurethane Waterstop can be easily applied to rough or smooth concrete surfaces, and into difficult to get at places that are a challenge for regular waterstop products. Furthermore, after hardening it has better physical properties than those of conventional putty type sealants. Because it is a moisture-cure, one component water-swelling sealant it can be easily applied with a standard caulking gun.