Abstract: Coupling joint seals, for oil well head high pressure control equipment particularly for the assemblies of riser tubes thereof on wireline equipment, have the coupling containing a seal constructed and arranged to permit the use of a rigid non-extrusion ring, preferably of yellow brass, as a retainer or back up ring as an element of the seal. The arrangement includes a groove cut into a cylindrical surface of a coupling member that enters an annular slot therein that shall contain the seal means to be disposed therein. The rigid non-extrusion ring is screwed or threaded through the groove and into the annular slot.