|Double walled glass system with filter. The Hot Glass System is the solution for everyone who wants to keep fingers cool while keeping the drink much longer hot.The double wall insulates hot and cold beverages alike with yet a second effect. No more damaged surfaces through wet vapor-film rings or heat marks as the double layer keeps them apart. No coaster is necessary anymore! Hot Design: Equally equipped with our ingenious permanent filter it allows you to enjoy your tea individually. Hot design for a "floating" tea experience.