From Golden Rabbit, the Enamelware Swirl Mugs, Set of 4 features:  This enamelware is made of carbon steel coated with a porcelain enamel and trimmed in stainless steel. There will be variations in the shading of colors and pattern formations which are the results of the hand-dipped process. Enamel steel Stainless steel rim Swirl collection Hand-dipped  Oven & stovetop safe Dishwasher safe Measures approx. 3.5" H Approx. capacity 12 oz. Imported.