Rezi-Weld Flex is a gray, two-part, pourable consistency, premium-grade, moisture-insensitive, epoxy joint filler formulation. When cured, it is semi-rigid, with a Shore D Hardness of 60. Rezi-Weld Flex was developed for use as a joint filler for saw cuts and construction joints in interior concrete floors subject to load bearing, wear or impact conditions, such as warehouse and industrial plants.