Purchased about three years ago and used once, I am now selling it as I have no further use for it. [Product Overview] This is a sleeping bag custom-made by NANGA. Rather than just a color variation, we've changed the structure and specifications. This is a sleeping bag designed with practicality and appearance in mind, intended for use in camping. The down on the back of a sleeping bag loses significant insulation when compressed. Therefore, we decided to leave the insulation of the back to the mat, and move all the down that was originally on the back to the sides and top, which should make it warmer. Also, by layering two fabrics, we've created subtle color variations that are difficult to achieve with a single layer. This layering also aims to improve the sleeping bag's overall insulation. It can be used throughout three seasons, but when combined with a flannel inner sleeping bag, it can also be used to some extent in winter camping, excluding the coldest periods. SPEC (Extracted from NANGA equivalent: UDD BAG 450DX) Comfortable Use Temperature / Lower Limit Temperature: 1°C / -4°C Down: 450g UDD Size: Regular