What's a bombproof sleeping bag for winter camping?

A: Several good choices here, Ty. For starters, take a look at the Big Agnes Farwell +0 bag ($189; www.bigagnes.com). It's rated to zero—as the name implies—and uses reliable Polarguard Delta as its insulation. Big Agnes does something interesting that some other bag makers are now mimicking (for that matter, Big Agnes mimicked this idea in the first place): there's no insulation on the bottom of the bag, the rationale being that a sleeping camper squishes that insulation anyway, rendering it basically dead weight. Instead, there's a sleeve in the Farwell into which you insert one (or, better, two) sleeping pads to provide your underside insulation. It works pretty well. There's a chance of a cold spot or two right at that angle where the insulation ends and the pad begins, but it's nothing severe. And the design helps cut the weight—the Farwell weighs three pounds, nine ounces, which is pretty darned good for a zero-degree synthetic bag.

You might also consider Integral Designs' North Twin ($210; www.integraldesigns.com). It uses PrimaLoft for insulation, and most readers know I favor PrimaLoft due to its very soft, down-like feel. The North Twin is technically a ten-degree bag, but that's a very conservative rating and Integral Designs makes very hardcore gear. I wouldn't hesitate to take this bag out in the winter, and one can always pack along a vapor barrier liner (many models—they usually cost around $30) for a lightweight add-on that lowers the rating below zero. Weight is three pounds, eight ounces.

An absolutely traditional synthetic bag is Mountain Hardwear's 3rd Dimension ($220; www.mountainhardwear.com). Polarguard Delta insulation wrapped all the way around, contoured footbed, full hood—it's a bombproof, well-tested design. But it still has some good design touches, such as an expandable draft tube. You can open the draft tube up for more room and ventilation in warm weather, close it down for cooler temps, or open it and add another layer inside the bag for those minus-ten-degree nights.

Take a look at these and see what strikes your fancy. They're all good bags.

More sleeping bags reviewed in Outside Online's all-new Sleeping-Bag Buying Guide.