These custom steel spring washers were manufactured using high carbon steel material heat treated to 38-45 HRC with black oxide finish.  When flat, the inside diameter measures .126" and the outside diameter is at .245".  The thickness is set to .004" +/- .005" with our production parts mostly measuring around .007" in thickness.  In it's final shape the OD across the bent sides is at .231" +/- .005".  Production is typically done at 150,000 pieces at a time, which is the MOQ due to the tiny nature of this spring washer.