This insulated glass mug is crafted from high-purity borosilicate glass, a safe, transparent material that's heat-resistant and resistant to cracking. Its unique double-layer insulation effectively prevents burns while locking in the temperature of your drink for extended periods, allowing you to enjoy your beverage at just the right temperature. The mug is crystal clear and textured, and the handle is designed to fit the curve of your hand for an extremely comfortable grip.