Multiple operating modes- Hot and cold functions can be used independently, or together, hot-steam and cool-mist functions have separate on/off switches and bright lighted indicatorsExcellent steam production-quickly produces pore-opening, muscle-relaxing, heated steam, or vapor. Curved, venture-shaped nozzle provides for even misting at the steam exit. Automatic circuitry turns off steamer if water level drops too lowPremium cool-mist generator- This unit features an internal ultrasonic humidifier which produces and diffuses a fine fog. This fog or cool-mist can both improve respiration and moisturize. Ultrasonic humidifiers are powerful, very energy efficient and they run quietly.