The Vapor Concentrate gives you total control over the amount of vapor released and the length?of time your concentrate will last. The Vapor Tunnel is designed to treat up to a 20,000 cu. ft. area. The tunnel can be placed on any flat surface or attached to the wall with simple Velcro tape. The Vapor Concentrate Squares/Bars are placed into the Tunnel by sliding one of the supply trays out and pressing the Square onto the pins. For a controlled release of vapor you will leave the plastic wrap of the Vapor Concentrate Square/Bar in place. You will cut a slit in the top of the wrap to allow the vapor to escape at a controlled rate.