Create a unique and innovative drinking experience. Two layers of lightweight borosilicate glass are mouth blown together to create a unique glass-in-glass effect. The result is a vacuum layer of thermal insulation that either keeps drinks hot and easy to handle or preserves the cold in your drinks without wet condensation. Included is a bamboo wood sealed cover that can be converted to a coaster for the optimal experience. 2-layer design creates a dramatic optical illusion, a pleasure to the eyes as much as to the mouth.