Made of borosilicate glass, which is lighter and more durable than regular glass Has high temperature and scratch resistance These double wall borosilicate glass mugs are 100% lead free Keeps your beverage hot or cold longer while the outside stays comfortable to touch Dual wall features create a dramatic optical illusion and prevents condensation Enable you to sip your beverage at an ideal temperature Perfect for espresso, latte, coffee, milk, tea, juice and various beverages