• Plug electrical knock-outs. • Molded in silver-gray color to resemble galvanized steel. • Install quickly with fingertip pressure, no tools required • Fit trade sizes 1/2"NPT to 1" NPT • Lock firmly in boxes/panels up to 1/8" (3.2mm) thick • Approximate head thickness .062" (1.6mm) • Made from 6/6 Nylon • UL and CSA approved • Flammability rating: 94V-2