SAFETY This glass is made of non-scratch borosilicate, heat resistant, condensation resistant, 100% lead free and BPA free.It is designed to provide you with the safest and healthiest high temperature product. DOUBLE LAYER DESIGN The double-layer design of this coffee mug utilizes double-layer technology. When the inner layer gets hot, the outer layer won't warm up, thus protecting your fingers from burns and keeping your liquid at the ideal temperature for longer. STURDY AND DURABLE This glass can withstand temperatures as low as -4 degrees Fahrenheit, so it's perfect for making iced coffee and keeping it for a long time. It's also microwave safe (heat resistant up to 302F) and dishwasher safe. VERSATILE This clear coffee mug is versatile and perfect for tea, coffee, lattes, espresso, cappuccino, smoothies and juices. The glass is so clear that the coffee seems to float in the air, making it the perfect companion for your breakfast and tea time.