Made of high borosilicate heat-resistant glass, double-layer insulation glass-form an efficient insulation layer. The double-walled design allows your glass to stay hot and cold longer than in regular glass, while the outside of the glass stays safe-to-touch. The body of the cup adopted Double insulated structure, can keep the hot for a long time when frothing or drinking boiled milk, and not burn hands. Is a very practical cup. Designed for Milk, Juice, Tea, Coffee and much more. A great humorous gift mug for coffee and milk fan.