1.High performace,low power consumption 2.High microstep,high torque 3.broad voltae range 4.wide output current ... ,so as not to damage the module2,GND:DC power cathode3,A+,A-:Stepping motor one winding4,B+,B-: ... metal shell , or use axle flows fan dispels the heat, to make the module run reliably for a long time ... ,installation dimension Stepping motor driver,1.3A-4.5A,high quality and reasonable price