Allows precise humidity control with a 20%-90% range. Change from 'humidification' to 'dehumidification' with a flip of a switch. Controls any 120 volt humidifier, dehumidifier or fan. Grounded piggy-back cord is safe and easy to use. Ventilation louvers help avoid water accumulation and possible damage to the unit. Built in 4% split differential. 15 Amps/120 Volt/60 Hz. 3 year warranty.