* Superior quality HYDY vacuum thermal series observes the stringent quality control in line with the Swiss SGS safety standards. It is made using advanced 18/8 (304) stainless steel food-grade, non-BPA (BPA free) and other harmful substances, it will not have any chemical change, easy to clean and more resistant to corrosion, allowing you to drink healthy water without worries. * Excellent thermal insulation effect Whether you are in your office, gym or enjoy the outdoors under the warm sunshine, double stainless steel bottle is designed for 12 hours hot thermal insulation and 24 hours cold thermal insulation, no matter in what kind of environment, you can enjoy cold or hot drinks.