This provides a constant source of oxygen for the smoker so it doesn't go out. Note the legs on the bottom to hold it up. It's modeled after the insert in a Rauchboy smoker but it's just made from a large soup can. I realize with pine straw this often isn't a problem. but any other kind of fuel, constant air can be an issue. I use what pine straw I have (my hives are under two big pine trees) but that is all burned up by the middle of May, and then I use burlap.