"Light enough to carry in the summer, but warm enough for deep winter in the Sierra Nevada," says our tester. "It may be the only bag you'll ever need." The versatility starts with the incredibly low weight for the warmth–and that starts with ultralofty 850-plus down that comes from fat French grey geese, birds that migrate at 30,000 feet in -60°F temps. Next, the mummy shape is hyperefficient without being constricting (but it allows for some gear storage at thigh level). And an interchangeable draft collar boosts versatility: Go collarless on mild nights; zip in the midweight yoke-style collar for cooler temps; or swap in the full wraparound version in the coldest conditions. Our tester used the full-winter collar during a December open bivy at 10,000 feet in the Sierra, with 55-mph winds, and pronounced the 4°F rating right on.
Another unique feature: Two hood-adjustment toggles clip together to allow easy, one-handed sizing. The smooth-running, full-length zipper allows for side ventilation, and the one-inch webbing zipper pulls are easy to grab with gloves on. The zipper is backed with a puffy draft tube that seals out even a hint of cold. The nylon shell and liner never felt clammy, and the absence of a side baffle let our tester shift more down to the bottom of the bag on warmer nights. The Bloody Mary mashes down to about 8 x 10 inches in its included compression sack. Nitpick: The storage bag is oddly small. $489; 2 lbs. 9 oz. (unisex reg); 3 sizes; valandre.com