13-3/4-ounce Doulbe Old Fashion, Set of 4 * Luigi Bormioli?s proprietary material called SON.hyx allows the glasses to be extremely break resistant and transparent. * 25 Year Guarantee! The guarantee covers chipping on the rim or foot as well as any discoloration or cloudiness resulting from dishwashing. * Innovative glassmaking techniques produce perfectly smooth rims and edges * 25 year guarantee covers rim and foot chipping as well as discoloration