AZZUTORK Speed Controller Inline Fan Duct Variable Blower Rheostat Control Air Vent 4031

The KB Electronics Rheostat Speed Controller offers easy control of fan speed and noise and is versatile to work with a variety of fans. Rated for light motor loads up to 3 amps, this control can increase the usefulness of all types of fans and blowers. "Low" can easily be set with internal "pot" to different voltages by using a small screwdriver. ("High" remains delivering 115 VAC, but "Low" can be set to from 115 VAC down to any VAC you need (100, 90, 60, etc.). As you receive it the Low End voltage is roughly 53 VAC. Rotate clockwise to increase the low end voltage and counterclockwise to raise the low end voltage.