The Cool Grip X-Tumbler was built to keep your hands cool when drinking hot liquids. This is made possible by the Cool Grip unique design that reduces surface temperatures and heat transfer, allowing you to hold your hot tea and coffee firmly without burning your fingers. In addition, a rigid ring made of glass-reinforced nylon keeps the rim of this medium-sized 12 oz /350 ml tumbler stable. All materials are BPA-free and certified to EU food-grade standards. FEATURES:- a Collapsible tumbler with heat protective fins a Folds flat to a 5/8" / 15mm thick disc a Heat resistant, BPA-free, food-grade silicone a Calibrated as a measuring cup a Nests with other X-Series products