Thanks to welded seams and a protected zipper that can withstand a downpour, the Spirit SL is a standout in the growing category of waterproof-breathable down bags. The 800-fill down squashes small in the pack, and the cut is pleasantly roomy, especially in the footbox, which lets the dogs flop naturally while the baffles drape snugly. The upshot: toastier feet. Testers were plenty warm sleeping under the stars on dewy 40-degree nights in eastern Washington. 32°F, 2.2 lbs; www.mountainhardwear.comBonus: Every bag should come with a waterproof compression sack, like the Spirit's.Bummer: More than three bills for a bag that bottoms out at freezing? Ouch.