The YETI Rambler Tumbler is made with kitchen-grade 18/8 stainless steel and double-wall vacuum insulation, which allows the tumbler to retain cold (or heat) twice as long as the average plastic tumbler. The exterior wall is built with extra steel for superior durability, and the crystal-clear lid allows users to see the level of their beverage. The Rambler Tumbler is available in two sizes and is BPA-free.
You can find more information on the Yeti Coolers website.