My Bevi travel mug is a superior grade 18-8 304 stainless steel vacuum insulated construction. Copper coating on the outside of inner steel wall adds a 3rd layer of insulation. Rugged powder coat paint finish for maximum durability. Polished steel accents. Comfortable ergonomic handle. Dual function lid: Color matching straw included for use with the sealable straw hole, and an ergonomic raised lip with slide closure so you can sip how you want, when you want. Lid slide closure intended to help prevent splashing and to retain hot and cold beverage temperatures. Lid is not leakproof and won't prevent spilling. Sleek design fits most cupholders. Made with BPA Free materials. Keeps hot or cold for hours.