The Stainless Mug features an electro-polished SlickSteel® finish interior that is corrosion resistant and repels stains. The tight fitted flip-open lid with a safety lock makes drinking from the mug easy and prevents beverages from spilling.•Stainless steel vacuum insulation keeps beverages hot or cold for hours•Stopper disassembles for thorough cleaning•2-step lid release process prevents excess condensation on the stopper from being flung off while the lid opens•Air vent on the mouthpiece allows beverages to flow out smoothly, without gushing or overflowing•1-1/2" wide mouth opening•Made of BPA-free plastic and 18/8 stainless steel