Flex ShotÂ® is the revolutionary super thick, rubber sealant to caulk, bond and seal virtually everything. Because it's so thick, you can fill huge cracks and holes and stop tough leaks instantly. Flex Shot comes out nice and thick and will cling to any surface. Then it turns into a stretchy rubber seal that's virtually indestructible. The free extension tube makes even hard-to-reach repairs perfect every time.