Duralex (Pack of 6) 1046AM24A1111 Water/Juice Glass Set  (560 ml, Clear)

What makes Duralex® glass so strong is the tempering process. It consists of rapid ventilation cooling of the entire glass product, which has been previously heated to a temperature of approximately 700°C. This treatment creates controlled stresses in the glass that improve most of its physical qualities: resistance to mechanical stress and thermal shock (sudden temperature change). This makes Duralex® glass at least 3.5 times more resistant to mechanical stress than an annealed (standard) glass product. It is resistant to thermal shock of at least 130°C.