Sweese 413.101 Glass Coffee Mugs - 12.5 oz Double Walled Insulated Mug Set with Handle, Perfect for Latte, Americano, Cappuccinos, Tea Bag, Beverage, Set of 2DOUBLE WALLED DESIGN The double layer glass mug set keep hotter and colder than the normal single walled glass and ceramic mugs. Cool to touch, without burning fingers CLEAR BOROSILICATE GLASS 100% lead free. Sweese glass cups are made of mouth blown borosilicate glass which is more durable than normal glass and is well known as the purest and safest material to contact with water. 2 layers with a smooth and clear look, your drink will seem to float