The Libbey DuraTuff® treatment is a special thermal afterprocess for "pressed" tumblers and stemware such as Gibraltar, Winchester, Inverness, Paneled Tumblers, Everest and Dakota. The DuraTuff® process is performed only on the upper portion of pressed tumblers and stemware to increase their resistance to thermal and mechanical shock. Libbey's DuraTuff® process produces durable glassware with prolonged service life for the foodservice industry. Look for the DuraTuff® name embossed on all Libbey DuraTuff® products. Libbey now offers DuraTuff® plates and bowls which are treated over the entire surface of the product.