Flex-Seal plural-component aromatic urethane utility sealant from Sealing Systems has 800 percent elongation and a tensile strength of 3,200 psi. It prevents inflow/infiltration and provides corrosion protection at the grade-adjustment ring section or joint section. It provides a seal that will pass a vacuum test according to ASTM standards. The internal seal is manually applied using a paintbrush, and the kit is designed to cover 12 vertical inches on a 27-inch-diameter manhole. 800/478-2054; www.ssisealingsystems.com.