J.W. Winco GN 749 Threaded Pipe Plugs, Steel, Zinc Plated, w/ NBR Synthetic Rubber Seal, M 22 x 1.5, J.W. Winco, Mfr#: 749-M22X1.5-A

Gn 749 threaded pipe plugs seal is retained in a groove undercut in the mating face, which prevents it from dropping out and from extruding when the plug is tightened. For this reason the seal can be of a softer material which offers better sealing.