The Rambler 30 Oz. Is The Tumbler That Gets You Through The Day. Your Morning Brew Will Stay Hot Or Your Iced Coffee Will Stay Cold — So Take Your Time. Kitchen-Grade Stainless Steel With Double-Wall Vacuum Insulation Work Together Protect Your Drink At All Costs. Like The Entire Rambler Drinkware Family, The 30 Oz. Tumbler And Magslider Lid Are Dishwasher-Safe For Easy Cleaning. While The Magnet On The Included Magslider Lid Adds An Additional Barrier Of Protection For Keeping Drinks Contained And Preventing Heat Or Cold From Escaping, This Magnet Slider Is Not Leakproof And Will Not Prevent Spills.