What’s so Souper? Boston Warehouse Souper Mugs are made of high quality stoneware, with a plastic lid that has a steam vent cover, freshness date dial, and a rubber gasket for an air-tight seal.24oz Souper MugMULTI-PURPOSE – Prep, cook, serve, and store all in one dish. A must have for weekly meal prepping!PRACTICAL – Perfect for breakfast, lunch or dinner or even appetizers. Think overnight oatmeal, power bowls, soups and stews, or leftovers from last night’s dinner.PREVENT FOOD WASTE – Use the unique ‘date-dial’ to set when the meal or leftovers were stored. No more wondering how long that meatloaf has been lurking in the fridge.DURABLE AND REUSABLE – Made of durable stoneware, this 24oz mug is freezer, microwave, oven (without lid, up to 375 degrees) and dishwasher safe. Plastic lid is freezer, microwave and top-rack dishwasher safe. Easy to clean and use over and over again.SAFE AND HEALTHY – Boston Warehouse stoneware Souper Mugs meet FDA requirements for food use. The BPA-free plastic lids are vented for release of steam and splatter prevention while microwaving.