Ball check valves allow free flow in only one direction, prevent backflow, and are for applications where poppet style valves may not be suitable (such as media with contamination, viscous fluids, etc.). They are trouble free with large flow paths. The need for closely mating surfaces and sliding parts has been eliminated by the conical tension spring and seal seat design. Kepner's Flexible Seal Seat™ design combines metal-to-metal contact with a resilient seal seat to ensure bubble-tight shutoff of liquid or gas, and long service life. Features and Benefits: Flexible Seal Seat™ for zero leak (bubble-tight) seal at low and high pressures O-Ring seal positively secured Stainless steel ball design; no sliding parts Exclusive conical tension spring design allows for greater flow Handles contamination, viscous liquids and slurries