The SC-3M is a highly practical and durable variable autotransformer, commonly referred to by the brand name VARIAC. It functions as a voltage regulator or controller for a variety of applications in laboratories, engineering workshops, and testing environments. The unit features a maximum power rating of 300 volt-amperes (VA) and is intended for use with 60Hz AC input power. A single knob controls a brush assembly that slides along a single winding, allowing users to precisely dial in any desired output voltage from zero up to 130 volts. The robust metal construction ensures longevity, while the simple design makes it a dependable tool for adjusting power levels or testing equipment at different voltages.