SealGuard II is highly reactive, dual-component hydrophobic polyurethane with a 1 to 3 second reaction time. It is designed to stop rapid water flows into concrete or other underground structures. It won’t shrink, gives off no VOC’s, and requires no special breathing apparatus. Each static mixer has a patented check valve that allows for use of a partial tube set. The valve also keeps the polyurethane, which can be hot during reaction, safely in the mixer. SealGuard Inc. 866-625-4550.