Using the same principle as the Temperature Controller, the Humidity Controller either shuts OFF or turns ON an appliance when a set Relative Humidity is reached. Range is from 30 to 90% RH. Great for use with a humidifier to keep the right amount of RH when dry-curing. Easy to use 3-button operation. ±5%RH Accuracy. Controls up to 15 Amps and 1800W. NIST Traceable.