Treesleeves are made from one solid piece of wood, and lined with a ring of cork to help your beverage keep cool and finished with non toxic polymerized linseed oil. Unlike Koozies (a registered mark), this drink sleeve is made of wood. Wood from the forest of New England. They fell the trees, mill the wood, and have it specially kiln dried. It does not contain toxic petroleum products. It is guaranteed to give you that warm fuzzy feeling every time you slide your favorite brew into it.