The Rambler 30 oz. is the tumbler that gets you through the day. Your morning brew stays hot, and your iced coffee will stay cold - so take your time. Kitchen-grade stainless steel with double-wall vacuum insulation will protect your drink at all costs. 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, please note - this magnet component is not leakproof and will not prevent spills.