It's not a myth; there really is a tough 14 oz mug that keeps its contents hot or cold all day. Introducing the Yeti Rambler Mug--the most durable, most over-engineered camp mug you'll find. Made with kitchen-grade, 18/8 stainless steel, it is puncture and rust resistant for long-lasting, reliable use in the great outdoors. The double-wall vacuum insulation means your hot and/or cold drinks, soups, chilis, and more will stay that way. This mug is built for the wild.