I purchased this item new and have kept it in storage, unused. Sea to Summit Retail Price: 62,260 yen Features a lightweight and compact 10D shell and 7D lining. Employs highly compressible RDS850+ premium goose Ultra-Dry Down. This is a quilt type, so the back is open. Since the loft on the back side is compressed, the warmth doesn't change much whether or not there is down there. However, in the case of a quilt, the down that would have been filled on the back side in a mummy type is brought to the front, so warmth can be obtained with less down (quilts are often warmer with the same amount of down). I will also include the compression bag and documents such as the certificate. The certificate is not about the product's specifications, but rather, it is a verification for each individual item, so you can feel the reliability and careful craftsmanship. The product specifications state that the down cluster is 90%, but this individual item has 95.7%, so it may be slightly warmer than usual. The fill power is also as stated, with a result of 850 fill power. The -6°C rated 850FP Revelation down quilt (regular/regular) from Enlightened Equipment has a down fill of around 455g (16.08 ounces), while this one has 500g, so it is estimated to be as warm or warmer. Furthermore, this is water-repellent down, so it is expected to maintain warmth better in environments where condensation is likely to occur. Fill: 850+ fill power Ultra-Dry premium goose down Weight: 725g Down weight: 500g Size: Regular = up to 183cm Comfort temperature = -10 to -4 degrees Celsius The down will be stored uncompressed while it is for sale. It will be shipped in the storage mesh bag, not the compression bag. Features: For 3 seasons (spring to autumn)