The stainless steel thermos flask keeps hot or cold for longer than any other vacuum flask thanks to a vacuum and copper layer. In addition, the double-insulated, leak-proof lid ensures the bottle's phenomenal functionality. The type-304 stainless steel of the Blck is coated with a matt black powder coating, giving it a sleek yet striking appearance. Something that fits into everyday life has to be practical and not involve any extra effort. Just like the Flsk. The Blck is an uncomplicated, good-looking companion through urban spaces and the periphery. Simply rinse it out after use and that's it. There's never been a drinking bottle like this one.