Save space by transforming your Rambler® bottles with Yeti's insulating two-in-one companion, the Cup Cap. Not only is it compatible with any Rambler bottle, it offers twice the functionality. As an insulated cap, it keeps your coffee, tea or even whiskey at the perfect temperature. And when you twist it off, you have a double-walled, vacuum-insulated cup. Note: Do not use the Rambler® Cup Cap for bottles for carbonated beverages or for storing food or perishable foods.