The SPC series plastic are PVC, polypropylene, nylon plastic check valves and have 302 stainless steel springs, 316 stainless steel balls, and EPDM seals. 1 psi spring is standard with optional 1/3, 3, 5, 7, 10, or 12-pound springs. Available in barbs, MNPT, FNPT, Push-in connections with multiple combinations. Hastelloy® spring, PTFE ball, and FKM O-rings for aggressive environments are available.