Model : 15587 DuraTuff Treated Use Traex rack TR-6B with this Restaurant Basics DuraTuff Double Old Fashioned Glass Clear United States This Libbey 12 Ounce double old fashioned glass has been treated with Libbey's patented DuraTuff thermal after process for pressed tumblers, which gives the top portion of the glass maximum resistance to thermal and mechanical shock. When you see the embossed DuraTuff name on your product, it means you're getting the longest service life in the foodservice industry. Model #: 15587 DuraTuff Treated Use Traex rack TR-6B with this Restaurant Basics DuraTuff Double Old Fashioned Glass