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.The bedroom humidifier with top fill design has a flat surface and lareg opening that allows you to refill or clean the tank very effectively.