Double-walled, copper-coated insulation keeps drinks warm for 14 hrs, cold for 26 hrs; no condensation Made from food-grade 18/8 stainless steel; 100% BPA-free and leak-proof Durable and long-lasting; can be used for many years without degradation in quality or performance Versatile for various activities: hiking, biking, gym, work, school, and home use 18 oz and 22 oz sizes fit most cup holders in cars, bikes, strollers, and bookbags for convenience