This is an amazing bag for what it is. It truly does weigh only a pound, and packs incredibly light/small. A great racing bag, but not surprisingly, it’s not the warmest out there. Adding a bivy layer helps, but take the 35 (or 40, depending on where you read) degree rating seriously.

No real problems with durability, even though the bag feels somewhat fragile. Mine spent many a restless night right on the ground, with little to protect it. I did get two small tears in it (feathers started coming out). Easily fixed with duct tape, and still holding fine.

I used this bag for years, for both races and tours, but I am happy I upgraded to a warmer and slightly heavier bag.

A really, really cool bag. Both literally and figuratively. I take most of my temp ratings as ‘you will be comfortable naked in this bag down to X…’ Maybe not so much with this one. Probably a little closer to a 40 or 45 bag. That said, it is a damn fine piece of ultralight gear. While people brag about their super light sleep system, you can rest assured your full sleeping bag is probably lighter than their 4’x4′, handmade, locally sourced, totally organic, free range goose down quilt. That said, the bag is not without it’s shortcomings, in addition to the aforementioned generous temp rating.

-The zipper is a bit of a pain, not because of it’s short length, but because it is an open-end zipper. Kind of a silly thing to have when the zipper is only at your thigh.
-The hood functions more as a drawstring closure, than a true hood. Not necessarily a bad thing for my 5’8″ frame, and my rolly-polly style of sleeping, but worth noting.
-The lightweight and temp rating are both due to a fairly light down fill. Something that is definitely felt if you are a sidesleeper or otherwise compress the fill in the admittedly narrow girth of the bag.

All in all, a bag that serves its purpose for fast and light back or bikepacking. If you are utilizing all your clothing in conjunction with the bag, it can certainly go below freezing. If not, it’s not quite a 3 season bag.

Like any piece of equipment, the measure of its value is ones ability to use it efficiently. This bag is designed for experienced minimalist users, individuals that condition themselves to the extremes they will be using the bag.

I can’t believe this bag is still kicking after all these years and trips. It came along for 4 months of bikepacking on the CDT and is still in tact and just as ‘warm’ as I can remember. It’s now ~10 years old and has many nights of use, not to mention being maximally compressed over and over to fit in various bags that are truthfully too small for it.

It’s still a little smaller than I’d like for really good sleep, but I could have gotten the larger version. With less space/dead air I feel like it makes it a warmer bag.

I’d still highly recommend it, or similar, from WM.

I have owned this bag for 11 years. One suggestion I would make is getting a silk liner. It weighs almost nothing, takes up little space and adds 6 or 7 degrees. As is, this bag is probably 36-38 degrees and the liner really helps. Overall, I think this is a great bag.