Casa Bellante&reg; (Set of 4) Double-wall Glass Tumbler - Borosilicate Glass 14oz. CASA BELLANTE DOUBLE-WALL GLASS TUMBLER - (Set of 4) DOUBLE-WALL THERMAL INSULATION - double-wall tumbler creates insulation which prevents condensation and keeps your beverage cold for longer ELEGANT, HIGH QUALITY BOROSILICATE GLASS - double-wall design creates elegant floating appearance while adding strength and durability HANDBLOWN BY EXPERT CRAFTSMAN - each tumbler with be unique due to the handblown process DISHWASHER AND MICROWAVE SAFE; not for use with metal utensils