The Cigar Oasis Auxiliary Fan kit adds two additional fans to your Cigar Oasis II XL Display Case Humidifier. They simply plug into your Oasis II XL unit and can be placed inside the humidor to assist in humidifying more consistantly in larger humidors. We have personally used Cigar Oasis IIXL auxiliary fan kits with great success in our larger display humidors and guarantee their performance.