These beverage koozies keep cans and most sizes of bottles insulated. They're comfortable to hold and help keep beverages at their ideal temp for a longer period of time. There are four types: maple, lacewood, mahogany/maple, and lacewood/maple. All finished with high performance poly except the lacewood which is finished with Waterlox. Each shell encapsulates a neoprene sleeve. A hole at the bottom allows you to easily push the can out of this sleeve from below while a special ridge at the top prevents the sleeve from pushing out with the can. The technique is called "segmented turning", which is normally used to make high end vases, sculptures, etc.