Handcrafted at High Temperature Using 2mm thick glass, we make almost the thickest glass straws, which means more durable and safer for the elderly and children. Easy to Clean We have cleaning brushes so you don't have to worry about the straw getting dirty Resist Heat&Cold Borosilicate glass is well known for having very low thermal expansion, making it resistant to thermal shock, more so than any other common glass. The maximum thermal shock range (the difference in temperatures it can withstand) of borosilicate glass is 130°C.