– 12 inch 300mm Rectangular Mill Hand Flat File Without Handle, Single Cut. – Made of high Carbon Steel – T12. – Tempered and hardened to min hardness HRC 65. – Very strong and made for extended tool life. – Precision milled second-cut/ double cut teeth increases the amount of materials removed with each pass and cuts and files rapidly – Suitable for steel, aluminum, tin, iron, copper. etc.