A Pack Tite Unit is used to treat items that may be infested with bed bugs. It can be used to treat suitcases and other items that can't be easily washed in hot water. Be careful not to allow any items to touch the heating unit. Place your item in the center of the rack. Place the metal safety rack on top of your item. There are also side racks available. Zip it closed. Make sure it is zipped as far as it will go. This will kill bed bugs and eggs, because it will heat items up to 140 degrees. Heat the item for 4 hours, and follow the specific directions on the model that you buy.