This standard is included in DIN Handbook 1 E, 15-6 E and 193 E. The widths across flats in accordance with this Standard apply to all 2-flats, squares, hexagons and octagons, even if they are not moved by wrenches. A selection of widths across flats of hexagon bolts, screws and nuts is given in DIN ISO 272. Squares and square holes for spindles, handwheels and crank handles shall be chosen in accordance with DIN 79 and squares for tools in accordance with DIN 10 Part 1.