Diguo Double-Wall Glass Coffee Cup, Insulated Glass Espresso Mug Glass Coffee Mug Tea Cup, Set of 2 (5.4-ounce/150ml) Set of 2 double-wall glass espresso shot mugs with 5.4-ounce capacities. Height9cm / 3.5 Lightweight, insulated, borosilicate glass; 2-layer construction resists heat and prevents condensation 2-layer design creates dramatic optical illusion and the sleek lines of the glass provide a comfortable hold for any hot or cold beverage. Handmade of heat-resistant borosilicate glass, these vessels insure that their contents will remain hot for longer while the glass itself remains cool to the touch. Its unique design is appealing to the eye when filled with your favorite beverage. With its double layer of borosilicate glass it appears as though the liquid is 'floating' within the glass.