The DRV8825 Stepper Motor Driver with Aluminum Heat Sink is a breakout board for TI’s  DRV8825 microstepping bipolar stepper motor driver.
The DRV8825 features adjustable current limiting, overcurrent, and overtemperature protection, and six microstep resolutions (down to 1/32-step).
It operates from 8.2 – 45 V and can deliver up to approximately 1.5 A per phase without a heat sink or forced air flow (rated for up to 2.2 A per coil with sufficient additional cooling).
 
Microstep resolutions: full, 1/2, 1/4, 1/8, 1/16, and 1/32.
Step and direction control interface
Step resolutions: full-step, half-step, 1/4-step, 1/8-step, 1/16-step, and 1/32-step
Adjustable current control lets you set the maximum current output with a potentiometer. 
Intelligent chopping control that automatically selects the correct current decay mode 
45 V maximum supply voltage
Built-in regulator 
Can interface directly with 3.3 V and 5 V systems
Over-temperature thermal shutdown, over-current shutdown, and under-voltage lockout
Short-to-ground and shorted-load protection