These ball valves are made from glass reinforced polypropylene for strength and chemical resistance. The seats are made from PTFE for smooth operation and proper sealing characteristics. EPDM O-rings to handle most fertilizers and many chemicals. Double O-rings in stem area for extra sealing protection. Interlocking body and end plate to allow easy thread connection when installing valves. • Maximum operating pressure 100 P.S.I. at 70°F.