A set of original Jenaer Glas serving or food prep bowls. Made of thin but extremely durable borosilicate glass. The four bowls nest for easy storage. Diameter sizes are 3, 3.75, 4.75 and 6 inches. Volumes are 3.4, 5, 10 and 17 ounces. Dishwasher, microwave, oven, and refrigerator-safe.