General generator Material (select one)harden steel、stainless steel、tungsten carbide、aluminum、titanium alloy、PCD、soft material Hole type (select one)Φ 0.1~Φ0.2、Φ0.2-Φ1.5、Φ1.5-Φ3.0、Φ3.0-Φ6.0、EDM tapping, M3-M8