Why It's CoolHere's a sound argument for topping off your gear closet with an affordable, ultralight bag for warm-weather overnights. The Phantom takes up less room in a backpack than some fleece jackets and weighs less than a bag of gorp. » The zip is three-quarter-length (to trim weight) and sealed at the top end with an exceptionally strong hook-and-loop fastener. Unzip partway to vent and the Phantom won't lose its form. » The 800-fill down has amazing loft. » The shell, a tight weave of superlight nylon, may feel insubstantial, but it's notit resists water well and didn't abrade.Hmmm . . .If you're going to own only one sleeping bag, this won't be it. The Phantom simply isn't warm enough.