Features: Double-Wall Construction Heat-Resistant Borosilicate Glass Dishwasher Safe Microwave Safe Each cup has been individually crafted by expert artisans using heat-resistant borosilicate glass. These streamlined mugs keep coffee hot without burning your fingers, and keep cold drinks cold without any messy condensation. Lightweight, clear to the eye and smooth to the touch, these mugs fit neatly and comfortably into your hand. Includes: (4) Canteen Double Wall Mugs, 13.5 oz Features: Double-Wall construction keeps hot drinks hot and cold drinks cold Made from heat-resistant borosilicate glass Microwave safe Dishwasher safe Also ideal for serving rich, indulgent, chilled desserts Built to withstand extremes of temperature, ranging from -22º F/-30ºC to 350ºF/180ºC Safe to use in the freezer, oven and microwave Use care when placing ice into the glass to avoid fracturing the inner layer. If possible, add ice after the liquid. Avoid the use of automatic ice dispensers.