The ES Series of spring check valves (photo) feature a PTFE-covered, stainless-steel spring for positive closing, as well as a new disc design for smooth, trouble-free operation. Compared to ball check valves, the ES Series requires very low liquid-head pressure to close. That means more flexibility as to where valves may be placed in a piping system. Features include high corrosion resistance, smooth trouble-free operation and easy installation and maintenance. ES Series valves are available in sizes ranging from 0.5 to 3 in. End-connection options include socket, threaded, flanged or this company’s ChemFlare fitting technology. — Chemline Plastics Ltd., Thornhill, Ont., Canada