Stainless steel vacuum insulation keeps beverages hot or cold for hours; Heat retention: 190°F @ 1 hr. / 163°F @ 6 hrs.; Cold retention: 46°F @ 6 hrs. NEW Design: Leak-proof one-piece stopper with integrated gasket 2-step lid release process prevents excess condensation on the stopper from being flung off while the lid opens New air vent on the mouthpiece allows beverages to flow out smoothly, without gushing or overflowing Easy-to-clean, stain & odor resistant nonstick coated interior