The bottom is a separate plastic piece and can be secured on the bottom and also removed from the glass.
When the bottom is in place, it looks like a normal glass. You can perform all routines with this cleverly gimmicked glass that you would perform with a normal bottomless glass. However, this glass has more advantages: 15 routines, tips and tricks are described in the instructions.
Use the glass for mentalism, comedy, stage- and close-up magic!