A stepper motor is an electromechanical device which converts electrical pulses into discrete mechanical movements. The Pololu Bipolar 28×45mm 4.5V stepper motor is a small stepper motor with an operating voltage of 4.5V and a step angle of 7.5° that comes with a built-in mounting bracket. Its second color indicates that it utilizes a bipolar winding, meaning that it requires two conducting wires that have to be switched in order for the motor to rotate. Having a size of 28mm × 45mm and a weight of 32g, it is able to produce relatively small amounts of torque.