Dixon Air King couplings are recommended for use on virtually any type of pneumatic equipment. The maximum recommended working pressure for Dixon Air King is 150 psi at ambient temperature 70 degrees F. With the universal head, any fittings within that range can be connected regardless of hose shank or thread size. Unexpected twisting of hose assemblies can occur during use. To eliminate the possibility of accidentally disconnecting, each Air King comes with a Safety Clip. This clip is designed to be inserted into the locking holes on the fittings. The use of a Safety Clip assures the users that the fittings have been properly connected. Meets pressure requirements as specified in A-A-59553 commercial item description superseding Mil Spec.WWC-633D. Rubber seal. Made of iron. Blank end fittings have no outlet and are used to block the line at any coupling point. The end opposite the coupling head is flat, with an eye for a chain to secure the fitting when not in use.