Regular size mattress and a dedicated cover. Since there was no spit-up on the bed, I think it's in relatively clean condition. The cover has a slight scent of other laundry items from storage. If you are concerned, washing it before use will remove the scent. Product Details The "Air Impact" baby mattress has good breathability and a structure that makes it difficult for dust mites to live, so it is popular with customers who are concerned about allergies because they can "use it with peace of mind." Babies who tend to sweat a lot can sleep soundly without getting stuffy! Even when lying face down, it is easy to breathe, so moms and dads can rest assured! It also comes with a convenient carrying case, so it's a nice point that you can carry it to daycare, kindergarten, homecoming, or outings! The cover, which can be easily removed and attached with a zipper, uses a breathable mesh material and can be washed if it gets dirty. The filling can also be washed thoroughly with water, so you can always use it cleanly. Air Impact uses a special structure called "3D spring structure," which allows the flexible plastic resin to maintain a fiber shape that exhibits elasticity while entwining to contain air. This creates moderate firmness and excellent breathability, promoting an ideal sleeping posture. Air Impact boasts excellent breathability that prevents moisture from accumulating, and the mattress does not trap sweat, maintaining the same sleeping comfort throughout the year. It is also durable and maintains a 96% recovery rate even after 80,000 compression tests. Furthermore, no values were detected in the formalin test, proving its safety. Specifications ＜Size＞ 【70×120】 (Approx.) Width 70 x Length 120 x Thickness 3cm (filling) Product weight: Approx. 2.1kg ＜Material＞ Outer cover: 100% polyester (honeycomb mesh) Inner cover: 100% polyester Filling: Polyethylene resin