Perfect humidifier for home, large room, office, greenhouse and warehouse. Each purchase is 1 unit. 4.Safely moisturizes the air for up to hours of continuous operation so you can breathe easy and get more restful sleep. 3.Space Saving Design: designed for bedroom nightstand and office desk, fitting narrow space for better air wherever you are. 1.Safely moisturizes the air for up of continuous operation so you can breathe easy and get more restful sleep. 2.Design with a large capacity water tank, You can enjoy whole night sleep, frees you from refilling water frequently. It features an automatic shut-off safety that will turn off when when it runs out of water, preventing damage to the unit and ensure your safety.