GN7430-M20X1.5-A4 THIN HEX NUT STAINLESS: Stainless Steel, M20x1.5 Thread Size, Metric Fine

Sight plug and breather vent hex nuts mount breather elements, sight glasses, or threaded drain/fill plugs in thin-walled vessels or where threading the vessel itself must be avoided. These hexagonal nuts are chamfered on one side to increase the bearing surface and thread length.