The CONTROL RESOURCES INC 120V800C REV 3.1 SPEED CONTROL is a high-quality unit designed for HVAC and refrigeration systems. Made in the United States, this open enclosure speed control is specifically manufactured by Control Resources Inc. It is a single unit that is essential for controlling the speed of heating, ventilation, and air conditioning systems in various commercial and industrial settings. This product is a reliable and efficient component for maintaining optimal system performance and energy efficiency.