Prime Flex 920 is a single-component polyurethane injection resin used to seal gushing leaks, including wide gaps in concrete, where the structure is not subject to movement. This hydrophobic, super low viscosity polyurethane reacts with water and expands to form a closed cell, watertight, rigid foam. Due to its low viscosity, 920 is also used for permeation grouting of loose soils to consolidate soil particles and increase the load-bearing capacity. (For high strength or large void filling, see Prime Flex 985.) This material requires the use of Prime Kat or Kick Fast Kat to adjust the reaction time from 4-13 seconds.