Material steel, corrosion resisting, 17-4ph, cond h-900, fms-0131; surface finish 125.0 microin.; surface treatment passivated; o/a ht 0.510 to 0.520 in.; wd across outside flats on a hex shape, 0.430 to 0.439 in.; wd across inside flats on a hex shape, 0.218 to 0.222 in.; 5 through holes 0.094 to 0.096 in. Dia