Feathered Friends Penguin 20

[warmest]

Heading into polar bear territory? Get peace of mind with this bag. “On winter bivies, you typically feel pretty exposed and insecure,” says a tester who slept through gusts that nearly blew him off his pad, with windchills down to -30°F. “But this bag was like a force field that made the events of the outside world seem of little concern.” Packed with 850-plus-fill down, it lofts up a full nine inches, yet remains remarkably packable for its class—about basketball size.

A waterproof/breathable eVent shell keeps the down bone dry—even when puddles of tent condensation pooled on the bag’s foot end—and a two-inch-wide zipper flap prevents blowing moisture from penetrating. The hood has a reverse-differential cut*, so it surrounds the head like a customized cloud of warmth. Bonus: The roomy fit accommodates layers of puffy clothing that could push this bag’s comfort range down to about -40°F. $759; 3 lbs. 14 oz.; -25°F

*Reverse-Differential Cut Hood Fabric is cut larger on the inside than the outside, leaving room for the down to expand inward and fill in space around the head.

The Penguin mates with the Penguin Ground Sheet and converts to a two-person sleep system.

Used alone it is a roomy bag for one person. Zip-on hoods are available separately.