Any tumbler that's coming along for the ride needs to be tough enough to keep up. Our fan favorite Rambler™ 20 oz tumbler is made from durable stainless steel with double wall vacuum insulation to protect the temp of your beverage a tall costs. Like the entire Rambler™ drinkware family, the 20 oz tumbler and MagSlider™ lid are dishwasher-safe for easy cleaning. While the magnet on the included MagSlider™ lid adds an additional barrier of protection for keeping drinks contained and preventing heat or cold from escaping.