During cold and flu season, when allergies kick in, or the air is simply just dry, you can rely on Vicks Filter-Free Ultrasonic Cool Mist Humidifier. Vicks humidifiers for bedroom, kids room and beyond add necessary moisture to the air, and help ensure proper humidity levels in your home. Indoor humidity levels between 40-60% can help relieve cough and congestion, keep throat and nasal passages hydrated, temporarily relieve dry air discomfort, protect furniture, reduce static electricity and even keep plants healthier.