Now with the addition of the MagSlider Lid, the YETI Rambler Tumbler is better than ever! Featuring 18/8 reinforced stainless steel, DuraCoat Color Technology, and a magnetic slider, the 30 oz. Rambler Tumbler offers increased ruggedness, durability, and easy use. The MagSlider Lid slides smoothly back and forth, and protects from splashes and spills, whether driving on bumpy back roads or hitting some waves on the water.