Abstract: A conduit-connector coupling structure, otherwise sometimes known as a clamp-type connector, incorporates plural clamp segments operating to cam together flange members producing the coupling. Clamp segments are employed with connecting attachment means so as to draw together the flange members employed upon the tightening down of the clamp segments relative to each other. The forward flange portions of each of the flange members are provided with recesses mutually accommodating the insertion of a metallic sealing ring. When the flange members are drawn together the sealing ring is held in radial compression. The ring itself is provided with mutually spaced peripheral sealing lands on respective ones of its oppositely tapered sides. The ring is designed so that the recesses separating the lands will essentially maintain their integrity for all radial compressions to the ring which is intended for use solely within the elastic limit and below the yield point of the material of such ring.