The FSPV series poppet check valves come in black PVDF, back polypropylene, and white polypropylene with a choice of Buna-N, EPDM, Viton®, or Kalrez® seal. The standard spring is 302 stainless steel with a cracking pressure of 1/3 psi. Optional springs of 1 or 7 psi are available. These high-flow valves can be used in pressures up to 125 psi. Hastelloy® spring is optional. The inlet and outlet sizes are female NPT 1/4 inch, 3/8 inch, 1/2 inch, and 3/4 inch, and male NPT size of 1/2 inch.