thin steel
A 20-ounce double-layer 18/8 stainless steel thermos bottle with a powder-coated surface to prevent chips and scratches. Copper vacuum insulation can keep the beverage cold for 24 hours and hot for 12 hours. Equipped with a transparent push cover and matching straws. It is non-toxic and does not contain bisphenol A. A note for those who customize these cups. The 20 ounces of thin steel is slightly tapered (9.417 inches at the top and 8.722 inches at the bottom).