The double-layer glass mugs are made of 100% lead-free mouth-blown borosilicate glass, a well-known material for its durability and safety when in contact with water. It keeps hotter and colder than the normal single-walled glass and ceramic mugs. Cool to touch, without burning fingers. Savor the magic of our double-layered mugs! Your drink is suspended in mid-air, a captivating sight! Delight in the intricate art of coffee flower drawing, enhanced by the sleek, clear design. Elevate your coffee experience with style and visual enchantment.