VIVOSUN Variable Fan Speed Controller, Speed Adjuster for Inline Duct Fan in Ventilation System

3 Speeds: One switch, 3 modes; You can have low, mid, and full speed of the fan, suitable for different needs and situations with better ventilation, Lower Cost: With this fan speed controller, you don't need to run the fan at full speed all the time so that there is no waste of energy, Safe Operation: Built-in grounded plug for safe operation with all inline fans, Usage Scenario: This speed adjuster can be used on fans in places like grow tents, warm houses, home, basement, office and so on, Specifications: Voltage/Frequency is 120V/60HZ Max; Amperage is 15A; 6 ft. Cable; Plug: 3-pole, American(grounded).