If winter summits are in your sights, this is the bag for you. “The Snowline kept me warm down into the single digits, and it weighs half a pound less than other bags I tested,” said one staffer after lugging it up thousands of vertical feet and spending a week above treeline near Mt. Whitney. What’s the secret sauce? The mix of 850-fill down, a light and highly water-resistant shell, and some fancy baffling techniques that seal in the warmth. Alternating triangular baffles* run vertically through the core to maximize thermal efficiency, and overlap between baffles reduces cold air’s ability to seep in through seams. Trapezoidal horizontal baffles insulate the legs and footbox for some weight and cost savings. Testers were impressed: After one woke up with the footbox completely coated in ice due to tent condensation, he still couldn’t feel a hint of cold or moisture. A pair of draft tubes along the full-length zipper integrates into the collar to create a seamless barrier, all of which combined to retain heat extremely well. “I could sleep sans beanie in the teens, which I’ve rarely been able to do,” says a tester. Surprisingly, testers also found the Snowline extremely livable, which is rare among ultralight alpine-style bags. “I had plenty of room around my shoulders and feet, even after stuffing the bottom of my bag with damp socks and boot liners,” says one. $650; 2 lbs. 13 oz.; -4°F; mountainequipment.co.uk
*Baffles: These mesh chambers hold down in place. Different shaped baffles offer unique performance and weight benefits.