1.Spelcial head design for different usage. 2.125MM ,150mm, 175MM can be chosen. 3.Different harden can be required; Spelcial head design for different usage.125MM ,150mm, 175MM can be chosen.Different harden can be required;4 tooth, 5 tooth.Meterial can be use 45# steel. And also can be made of 40CrMo.And different harden can be treat different by different requirement. Chisel of air hammer