1.High performace,low power consumption 2.High microstep,high torque 3.broad voltae range 4. ... current:1.3A-4.5A3.Mircostepping:1(1.8º),1/2,1/4,1/8,1/16,1/32,1/64 ... When ambient temperature is high or working current over 2.7A, fix the module on big metal shell , or use axle flows ... fan dispels the heat, to make the module run reliably for a long time.2, Half current automatically: if control machine not ...