This is a Montbell Alpine Burrow Bag Thermal Sheet. It can be used in conjunction with a sleeping bag to lower the compatible temperature by about 5°C. It can also be used as a standalone sleeping bag. The Montbell Alpine Burrow Bag, made with EXCELOFT material, is a lightweight and compact sleeping bag. It is made of synthetic fibers, making it highly water-resistant and very convenient. In winter, I used it inside a three-season sleeping bag to increase warmth, and in summer, I used it by itself or as a blanket. [Material] Outer fabric: 30-denier Super Multi Polyester Taffeta [Water-repellent finish] Lining: 30-denier Super Multi Polyester Taffeta Insulation: EXCELOFT® [Weight] 542g [Color] Dark Gray (GM) [Storage size] Φ12×24cm (2.4L) [Accessories] Stuff sack *Please understand that this is a home-stored item and has been inspected by an amateur before purchasing. *We generally cannot hold items for extended periods. *We cannot accept complaints after purchase, so please purchase only after fully understanding this. *We cannot respond after you have left a review, so please contact us before leaving a review if you have any issues. *Only those who understand used items are welcome. *Please feel free to ask any questions you may have or any points that concern you.