TherMax double wall vacuum insulation for maximum temperature retention, hot or cold. Double wall foam insulated cup with stainless steel outer wall. Patented Twist 'N Pour stopper lets you pour without removing the stopper! TherMax vacuum insulation virtually eliminates temperature change by creating an airless vacuum space between two stainless steel walls. The result is an insulation layer that performs better than any other. A superior insulated container you can depend on to keep your beverages hotter, colder, fresher, longer. Unbreakable stainless steel interior and exterior walls. TherMax insulation layer. Made in China.