STACKABLE AND INSULATED FOR COMPACT STORAGE AND HOT BREWS. This mug is loaded with top-to-bottom insulation to keep your coffee hot from the first pour to the last sip. And it’s a space saver. When the lid is removed, the built-in grooves on the bottom help it nest perfectly with another just like it. Like the entire Rambler® Drinkware Family, this stackable mug and included MagSlider™ Lid are dishwasher safe making them easy to clean. Each mug is sold separately. Please note: Do not place mug over external heat source or open flame. Vacuum seal or other damage may occur. This magnet slider is not leakproof and will not prevent spills.