High borosilicate glass contains high boron and silicon, with boron content of about 12.5% to 13.5% and silicon content of about 78% to 80%. On the contrary, other types of glass may contain different compositions. High borosilicate glass has low expansion coefficient and excellent rapid cooling and heating resistance. This means that it has good thermal expansion and cold contraction ability when the temperature changes, and it is not easy to crack or produce stress. In contrast, tempered glass has high strength, but poor tolerance to rapid cooling and rapid heating. In daily use, high borosilicate glassware is usually tempered to improve its strength and durability.