20 Oz Himalayan Tumblers feature double wall construction with stainless steel in the interior and exterior that offers great insulation for both hot and cold liquids. There is a spill resistant slide action lid with rubber gasket. Empowered with vacuum insulation technology, these stainless steel tumblers can hold 18 oz liquid and can keep the drink hot or cold for 6 hours. BPA-free and FDA compliant.