Specifications: M1.1, M1.2, M1.4, M1.6, M1.8, M2, M2.5. Material: 4241 high speed steel/steel ball bearings, suitable for steel plate soft metal, such as aluminum, flat iron. High speed 6542 steel. All steel design with chrome finish for the highest durability. A fine example of precise ratchet action for high quality work. Easily switch from left to right, or locked for non-ratcheting use.