Plast-O-Matic Valves Inc., of Cedar Grove, N.J., announces its complete line of self-sealing thermoplastic check valves for corrosive and ultrapure liquids. Designed to safeguard process systems, Series CKS maintains a positive closure even in the absence of reverse pressure. Offered in 1-½??, 2″ and 3″ pipe sizes, the design uses a spring encapsulated with Teflon® PFA to protect liquids from contamination. The encapsulation technique is an advantage over coated springs, which tend to flake and corrode over time.