Flex-Grip™ 550 is an all purpose, fiber-free, duct sealant for use on all types of metal duct, glass fiber duct board and flex duct, as well as duct fabric and flexible tubing runouts. Distinguished by its ability to accommodate minor vibration and movement, Flex-Grip™ 550 stays flexible to save call back labor. Flex-Grip™ 550's excellent coverage rates and easy brush-on application provide low installed cost.