For the pro's Pro, the toughest of the tough and those who demand the very best, the 18oz master vacuum bottle offers extreme durability and thermal retention. The 1.0mm 18/8 stainless steel is rust-proof and naturally BPA-free while the quadravac insulation keeps drinks hot 12 hours, cold 16 hours, or iced 48 hours. Also featured is a steel-lined pour thru stopper so no plastic comes in contact with your drink, and the bottle is dishwasher safe.