Etched. 2 Sides.18/8 Ss 0.4-0.5 Mm Exterior; 0.8Mm Polypropylene Lid ( As Of 1/7/15) 18/8 Ss Interior; Vacuum Insulation 5 Year Warranty; Chemical Etched With Stacked “Skim Milk”. Retention: 4-6 Hours; Dishwasher Safe; Parts: Lid (Ssnlid), Base(Ssnbasess); Date Code: Embossed Into Handle-Single Dial; Product Box: 4.5 X 4.5 X 12.0.