#900 Hydro Sealant. #900 Is A Single Component Hydrophilic Polyurethane Chemical Grout. When It Comes In Contact With Water It Quickly Expands To Form A Tough, Flexible, Closed Cell Foam Which Bonds Extremely Well To Concrete. When Cured It Becomes An Extremely Effective Barrier Against Water Penetration.Applications:- Basement Cracks- Manholes- Swimming Pools- Tunnels- Cold JointsBenefits:- Single Component [No Catalyst Required]- Extremely Flexible- Very Tough Foam- Up To 700% Expansion- Penetrates Pores Of Concrete ForSuperior Bond