The U350 Digital Warm or Cool Mist Ultrasonic Humidifier fulfills all wishes. The innovative top fill design allows the humidifier to be filled on-the-spot by lifting the lid and is controlled using surface touch controls and an LED display. The AUTO mode automatically humidifies the room air to an optimal 45% relative humidity. This is measured by means of the built-in hygrostat which can be adjusted as desired. The U350 refreshes with a cooling mist in the summer months, and it provides fast and efficient humidification in the dry winter months with warm mist. The included 2-in-1 water filter A250 AQUA PRO helps the U350 provide pure humidification without residue.