The double-walled glasses from Bodum are made of mouth-blown borosilicate glass, making them lightweight yet very durable. Even after years of use in the dishwasher, the glass will not become cloudy. Beneath the glass base, there is a hydrophobic silicone membrane that serves to equalize pressure between the glass walls. This allows the glass to breathe; therefore, no condensation forms on the surface when holding cold drinks, and the glass does not leave unsightly water rings. These glasses are also ideal for serving ice cream and other desserts.