REI changed everything but the name on this sack: Designers kicked up the goose down to 750-fill, changed the shell, and added a lighter, softer liner. The updates shave seven ounces off last year’s version. It kept us warm on late-fall nights in the Grand Canyon, but the tradeoff was that even our smaller testers found the Sub Kilo a snug fit at the knees. 20°F, 1.7 lbs; www.rei.com
Bonus: The low weight includes a full-length zip.
Bummer: The 20-denier shell is not very water-resistant.