Double-wall vacuum insulation with a narrower bottom to fit most cup holders. Powder coating. Can be used with optional slide lid. Not recommended for dishwashers, hand wash only. Seamless construction so there is no leak point. Hole on lid is big enough for a straw. The stainless steel band at the top without coating is approximately 1/2"(H). Polar Camels are made from 18/8 gauge stainless steel (18% chromium/8% nickel) - also known as Type 304 Food Grade.