5mm bulkhead union push to connect fitting is used to connect two 5mm tubing on both ends through a panel or other barrier. Bulkhead union fitting is used when there is a need to move 5mm tubing through some obstacle. Simply drill a hole, push one part of bulkhead through it, and then screw second part onto the other side. 5mm O.D tubing x 5mm O.D tubing bulkhead union push to connect fitting is made of nickel plated brass, POM release sleeve and stainless steel tube gripping claws. 5mm O.D tubing equal bulkhead union push to connect fittings allow for a fast and easy way to repeatedly connect and disconnect air or fluid lines.