High quality double wall stainless steel vacuum insulation construction allows the Stainless Mug to keep beverages hot or cold for hours. The tight-fitting flip-open lid with safety lock makes drinking from the mug easy, and prevents beverages from spilling.•2-step lid release process prevents excess condensation on the stopper from being flung off while the lid opens•Tight-fitted flip-open lid keeps beverages hotter or colder•Safety lock to prevent the lid from opening accidentally•A special manufacturing technique was used to round the bottle opening, making it smooth and comfortable to the touch when cleaning•1-5/8" (4cm) wide mouth opening•Made of BPA-free plastic and 18/8 stainless steel