COFFEE MUGS, ENJOY LIFE: Double walled, Borosilicate material, 100% lead-free. 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 in mid-air, what's an amazing! Insulated glasses can withstand temperatures ranging from -20°C to 150°C! you can enjoy your cup of coffee, espresso, cappuccino or tea warmer longer.When you have hot coffee, you won’t feel hot from outside and when you have cold drink,there is no condensation on the glass and table. UNIQUE DOUBLE WALLED GLASSES DESIGN: Keep your fingers safe and cool with heat resistant and double wall glassware, so beverages stay warm without you getting burnt!the outside surface always feels comfortable in hand. MICROWAVE AND DISHWASHER SAFE:Double insulated coffee mug give an extra luxury look in your kitchen or on your dining table. It's more heat-resistant, high transparency, thinner and light weight, but more durable than normal glass. It’s suitable for dishwasher and microware safe.but recommend to wash by hand. UNIQUE GIFTS FOR COFFEE LOVER IN YOUR LIFE: For 300ml of coffee, milk, espresso, latte, hot and cold, or just about any drink you can think of, these ultra light, clear double-wall mugs are the present you just can’t wait to give or keep for yourself! DESIGN:There is a small round hole design on the bottom of the glass coffee cup, in order to prevent glass mugs burst when used, allowing the glass to breathe in the process. It is sealed, and the water would not go in.