Each EasyDriver can drive up to about 750mA per phase of a bi-polar stepper motor. It is permanently set to use 8 step micro-stepping mode. (So if the motor is 200 full steps per revolution, you would get 1600 steps/rev using EasyDriver.) It is a chopper micro-stepping driver based on the Allegro A3967 driver chip. For the complete specifications of the design, read the A3967 data-sheet.
It has a variable maximum current from about 150mA/phase to 750mA/phase. It can take a maximum motor drive voltage of around 30V, and includes on-board 5V regulation, so only one supply is necessary.
Great for driving Nema 17 motors.