Add quick connection points for mechanical gauges and other diagnostic equipment to your line. These couplings are also known as test ports and diagnostic couplings. To take a reading, connect a socket to your gauge using a hose assembly. Then push the socket into a plug that’s permanently threaded into a test port on your line. No threading or unthreading is necessary. Add additional plugs to your line to take measurements at different points. To quickly move the gauge to a different test port, pull back the sleeve on the socket to disengage.

A complete coupling consists of a plug and socket (both sold separately). The plug and socket both have a shut-off valve to stop flow when the coupling is separated, so they're sometimes called double shut-off couplings. They meet ISO 15171-1, which is an international standard for dimensional and performance standards of flat-face diagnostic push-to-connect couplings.

Note: To ensure a correct fit, make sure that the plug and socket have the same coupling size. Pressure ratings are given for static (constant) pressure conditions.