The Bellyache Mountain provided good medicine for sleep-hungry campers exploring the Utah deserts. The slick shell material proved remarkably durable given its lightweight feel—resisting snags and tears even when dragged through the canyon camps along the Escalante River. The DownTek down is coated with a highly water resistant treatment that prevents water from turning the down into cold, wet little wads of feathers. The system kept our tester warm even after a night under the stars ended in a drizzling rain at dawn. And the modest weight and compact size rode comfortably in our packs.

Compressibility
The 700-fill down compress to a tight 8×8-inch brick, though the standard stuff sack measures 8×17-inch for easy packing. This bag isn’t the smallest nor lightest bag in its class, but it’s not too far off either category.

Warmth-to-weight ratio
The 700-fill down in the vertical baffles of the Bellyache Mountain proved quite comfortable within its rating. Indeed, nearly half our crew deemed it the warmest of the lot. Part of that high comes from the slim cut of the bag—there are no excess air voids to suck heat away from your body. It’s a very heat-efficient bag.

Comfort
The Bellyache Mountain runs a bit narrower through chest, waist, and feet than most of the others in the class but that created slight fit issues only for the burliest of our testers.

As a 6’2” 220 pounder myself, I found the chest section of the regular length bag just a tad snug—though the rest of the bag fit okay and I could sleep well enough in that length. Moving to a Long version gave me a little extra wiggle room in the footbox, and just enough space to twist and turn in the chest area as well. The key is making sure you get the proper bag length (and taper) to fit your own body.

Durability
After heavy use in rugged conditions, followed by a couple washings, the Bellyache Mountain looked essentially new. Nary a scuff, snag or tear to be found. It was one of the few bags that came out of testing totally unmarred.