Starfrit Gourmet Swirl collection offers double wall glasses made of borosilicate glass. The double wall concept creates an isolation barrier. Keeps the temperature of what is in the glass constant much longer than standard glasses. Also great for appetizers and desserts. No more rings on tables, there is no condensation on the glass. Dimensions: 5.11 IN x 4.52 IN x 4.52 IN. Coffee mug holds 360 ml/12-Ouncs. Borosilicate glass. Double wall clear glass. Dishwasher, freezer and microwave safe. The double wall concept creates an isolation barrier which keeps beverages at their optimal temperature longer.