The legendary Rambler 20 oz. Tumbler is crafted from sturdy stainless steel and is double-walled for superior insulation. Hot or cold, this tumbler will keep your beverage at the desired temperature. The MagSlider™ Lid has a magnetic component for added security, though it is not leakproof. Plus, the entire Rambler® Drinkware Family is dishwasher-safe for an effortless clean.