4pcs RepRap A4988 Stepper Driver + 4pcs Stepper Motor for 3D Printer,Reprap,Makerbot,Prusa Mendel

Step Motor Technical Specifications:
Part No.: 42BYGHW208
Frame Size: 42
Step Angle: 1.8 degree
Voltage: 12V
Current: 0.4A/phase
Resistance: 30 Ohm/phase
Inductance: 37 mH/phase
Holding torque: 6.3N.m
Rotor inertia: 2600g-cm
Number of wire leads: 4
Weight: 0.2 kg
Length: 34mm


A4988 Features:
Simple step and direction control interface
Short-to-ground and shorted-load protection
Five different step resolutions: full-step, half-step, quarter-step, eighth-step, and sixteenth-step
Intelligent chopping control that automatically selects the correct current decay mode (fast decay or slow decay)
Over-temperature thermal shutdown, under-voltage lockout, and crossover-current protection
Adjustable current control lets you set the maximum current output with a potentiometer, which lets you use voltages above your stepper motor's rated voltage to achieve higher step rates