Plastic tubing check valve prevents water back-flow when pressure falls. Useful for any tubing system and vacuum line. Maximum safe working pressure: 2 BAR (equal approx. 28.4 P.S.I.). Minimum safe working pressure 0,07 BAR at room temperature (20°C). PP inner disk: DUTRAL. Regular check valve size valve will fit tubing 8-9-10 mm (1/4" to 3/8") diameter depending on elasticity. Will withstand temperatures up to 100° C.