At first glance, this mug may seem ordinary, but take a closer look. It features insulation from top to bottom to keep your coffee hot from the first sip to the last. And it optimizes storage thanks to the integrated grooves on the bottom that allow it to stack perfectly on another mug. So whether you store it in the cupboard or pack it up for an adventure, it's so much more than a regular mug. The wide opening gives easy access to the contents, but will also cool it down more quickly. That's why the mug comes with the Rambler® Standard Lid. The Standard Lid and MagSlider Lid are not watertight and will not prevent spills. - Empty weight: 360 g