These punches are made from uniformly heat treated carbon steel & are used for removing pins in parallel holes. The pins should first be started with a hand or taper punch to avoid damage to the end of the parallel punch. The set of eight punches include one of each of the following. 1.5 mm., 2.5 mm., 3.0 mm., 4.0 mm., 5.0 mm., 5.5 mm., 6.0 mm., & 8 mm. (TIP Diameter: x 4 in. long) Pin length 25 mm.