Stainless steel vacuum insulation keeps beverages hot or cold for hours; Heat retention: 181F @ 1 hr. / 135 F @ 6 hrs.; Cold retention: 50F @ 6 hrs. | | Easy-to-clean nonstick coated interior | | Rounded sip area, designed to drink directly out of the mug | | A special manufacturing technique was used to make the body ultra-lightweight and compact | | 1-5/8 (4cm) wide mouth opening | |