Brightsteel bottle comes with inner surface made of high-grade stainless steel with a smooth easy to clean finish. Stainless steel with vacuum insulation keeps contents cold /hot for hours you can carry chilled water or your favourite beverage conveniently. Its superior insulation and food grade material keeps beverages hot/cold/fresh for hours. Insulation helps in temperature retention that keeps your favourite hot drinks without altering their temperatures for a prolonged period of time. The easiest way to enjoy a beverage anytime anywhere.