Any tumbler that’s coming along for the ride needs to ne tough enough to keep up. Our fan-favourite Rambler 591 ml Tumbler is made from durable stainless steel with double-wall vacuum insulation to protect the temp of your beverages at all costs. Like the entire Rambler 591 ml Tumbler and Magslider Lid are dishwasher-safe for easy cleaning. While the magnet on the included dishwasher-safe Lid adds am additional barrier of protection for keeping drinks contained and preventing, heat or cold from escaping, please note-this magnet component is not leakproof and will not prevent spills.