White Metal Kit: There were many K types of controllers. These were 600 volt rheostats that the operator used to propel the car down the tracks. The typical ones for streetcars (but there were many other varieties) ranged from the basic K controller to a K-36, depending on the motor horsepower and number of motors. Some had safety devises built into them. This one represents a turn of the century (the last one) that would handle a four motor car and had no safety (dead man) devises on it, nor any line breakers.