World’s lightest goose down sleeping bag

The Sea to Summit Spark SpI 40 is the lightest and smallest-packing bag in the world. Sea to Summit's website listed the bag at 12 ounces,  and the fill weight at only 6.3 ounces. But our own scale measured it at 12.4 oz. 

It could only really use this thing in the summer months, as the EN 13537 rating lists the comfort temperature at 48°F, and the lower limit at 40°F。