The Proco Style 711 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 711 valves can be engineered into the pipe layout with little concern for outfall clearance due to its “low slope” design.