Omega Technologies OM2-1522-2 Large Diameter Hi-Lok Protrusion Gauges, 5PC Set. Omega Technologies 5PC Set of Protrusion Gauges for nominal diameter Hi-Lok® and Hi-Tigue® fasteners in sizes 7/16”, 1/2”, 9/16”, 5/8”, and 3/4”. Measuring 1.8” square, these Omega Technologies Protrusion Gauges are easy to handle and provide plenty of reach to inspect larger fasteners. Omega Technologies Protrusion Gauges are made of 0.20” full hard stainless steel that insures a long gauge life. The large footprint helps stabilize the gauges against work surfaces.