Now with the addition of the MagSlider(TM) Lid, the YETI RamblerA(R) Tumbler is better than ever! Featuring 18/8 reinforced stainless steel, DuraCoat(TM) Color Technology, and a magnetic slider, the 20 oz. RamblerA(R) Tumbler offers increased ruggedness, durability, and easy use. The MagSlider(TM) Lid slides smoothly back and forth, and protects from splashes whether driving on bumpy back roads or hitting some waves on the water.