Model: KSB 20
We know we have a winner when our veterans want to hang on to a bag for “a little more testing.” After we pried it away, one said: “Never, in 30 years of backpacking, has something that packs so small kept me so warm.” The rating is spot-on: After a 12°F night in Wyoming’s Wind River Range, our tester was the only person in his group not complaining of being cold. The 850-fill down is supremely lofty and the draft collar feels as warm and silky as mink, yet the Z10 packs to cantaloupe size.
Waterproof/breathable fabric on the hood and footbox repelled condensation in Vermont’s Green Mountains. Elsewhere, the Pertex Quantum GL nylon breathes well enough that testers never felt sticky, even on 50°F nights (when the two-way zipper enhanced ventilation). The hood fits better than most, clinging snugly to one side-sleeper’s head as he tossed and turned. And the cut is surprisingly unrestrictive: One thrasher (who typically uses a rectangular bag for freedom of movement) reports. “It never felt confining.” Testers’ only wish? A stash pocket for storing small items. $420; 2 lbs. 3 oz.; 10°F; golite.com