Unlike traditional camp mugs, this double-wall vacuum-insulated body protects hands from hot or cold contents while keeping coffee, chili, oatmeal you name it well-insulated.These Ramblers come standard with the MagSlider Lid, the only drink lid that uses the power of magnets to keep your favorite drink on lock.While the MagSlider Lid adds a barrier of protection for keeping drinks contained and preventing heat or cold from escaping, Please Note The MagSlider Lid is not leakproof and will not prevent spills. Ramblers are BPA-free, dishwasher safe, and have a No Sweat Design to make sure your hands stay dry. The tough Duracoat coating on the colored tumblers won't crack, peel or fade.