The Proco Style 711/731 ProFlex check valves are engineered for installation on pre-existing pipe lines such as manholes, outfalls and vaults where the outfall invert of the pipe is close to the floor of the manhole or outfall. When a new installation is being designed, the 711731 valves can be engineered into the pipe layout with little concern for outfall clearance due to its “low slope” design. The new Style 711/731 check valves allow the valves to be installed without any costly and labor-intensive changes to the existing structure.The valve ensures zero potential for standing water.