The purpose of this tester for managing all types of stepping motors. 

A stepper motor is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps. Stepper motors operate differently from DC brush motors, which rotate when voltage is applied to their terminals. To rotate, each step motor needed from an external control circuit, such as a microcontroller.
Stepper motors, on the other hand, effectively have multiple "toothed" electromagnets arranged around a central gear-shaped piece of iron. The electromagnets are energized by an external control circuit, such as a microcontroller.

In the set:
Tester - main unit;
Stepper motor connector;

For more detailed information, click here...