Mainstays Portable Rechargeable Humidifier HU00-23481R uses evaporative high-frequency technology to convert the water into particles that are dispersed into the air evenly with 11.16 ounces Capacity and coverage area:116sq ft which can offer many benefits to your environment making your personal environment a more comfortable and enjoyable place throughout the year. The relative humidity is the amount of moisture in the air compared to how much moisture the air can hold. the higher the RH the more humid it feels. warm air holds more moisture than cold air. Raising the humidity level in a cool dry room can make it feel warmer and more comfortable. Humidifiers offer many benefits to your environment making your home a more comfortable and enjoyable place throughout the year.