STACKABLE AND INSULATED DOUBLE WALL DESIGN The double-wall design allows a pair of glass cups to be stacked for space saving. The 2-layer demitasse glass cups stay cool to the touch and keep drinks hotter or colder than normal glass or ceramics. LIGHTWEIGHT YET STRONG Espresso mugs are made of mouth-blown borosilicate glass, which is comfortable to hold and built for long-term use. PERFECT FOR ESPRESSO MACHINES AND SMALL COFFEE MAKERS Each mug holds 5 ounces to the rim. They can be reheated in the microwave for hot beverages or used for cold beverages. They are dishwasher safe, though hand-washing is recommended. AN IDEAL GIFT Espresso mugs are an excellent gift for family or friends on birthdays, housewarmings, weddings, parties, and Mother's Day. Wrapped in a gift box, they are sure to make a lasting impression. PRACTICAL USE SCENARIOS - At home or in the office: brew with an espresso machine or a small coffee maker for a quick 5-ounce serving. - In small spaces: stackable design helps save cabinet or shelf space in apartments, dorms, or studios. - For entertaining: keep drinks hot or cold while guests enjoy a stylish, easy-to-handle cup.