The NIBCO lead-free wroth copper solder-reducing coupling is used in residential and commercial systems such as potable water, air conditioning and refrigeration. The reducing coupling features solder cups. Health Care Facilities Gas and Vacuum Systems and the Compressed Gas Association, Pamphlet G4.1 medical gas, UL 207 Recognized to 700 psi select diameters.For aboveground useSolder connection requiredDezincification resistantSize range 1/8 in. to 8 in.439 psi maximum working pressureUsed to join straight lengths of tubing