mont-bell Sleeping Bag and Sleeping Bag Cover Set This is an outdoor brand, mont-bell sleeping bag and sleeping bag cover set. It has been used about twice, maintained, and then stored. Down Hugger 800 #5: ¥28,600 Breeze Dry-Tech Plus Sleeping Bag Cover: ¥18,000 This is a total of ¥44,800 worth of items, but offered for ¥15,000 (including shipping). It will be shipped in a storage bag. Thank you. The following is an explanation from the manufacturer's website: It uses 800 fill power "EX Down" for the insulation. EX Down is a high-quality down made only from waterfowl raised in harsh environments. The down balls are large and dense, so it has very high heat retention. Compared to general down with 550 fill power, it has about 30% higher heat retention performance. The fact that it exhibits high heat retention with a small amount means that the storage size is very compact. Another feature is the "Spider Baffle System" structure. Special threads called "Spider Yarn" are stretched inside, and down is entangled with them to prevent the insulation from shifting. Because there is no need for a quilting structure to prevent the insulation from shifting, and the seams are minimized, high airtightness = heat retention efficiency is achieved.