Laken"s Thermo Flasks have very high performance vacuum insulation that keeps your drinks hot for up to 12 hours or cold for up to 24 hours.? This is a double wall flask, made of 18/8 stainless steel, BPA free. They come in 2 sizes, 12 and 17 Ounce, with a push button cap. These Inox thermos has a neoprene cover and a velcro handle with Kukuxumusu or solid color designs.