REI Co-op  Flash Sleeping Bag

I partially agree with the reviewers that claim this is a bag geared for back sleepers but I am a side sleeper and the bag still does the job. I bought this for an 8 day hike to Yosemite NP and on two mornings we woke up with frost covering the tents. I found that by adding a Sea to Summit thermoliner, long underwear and a thin fleece shirt I was reasonably warm even in sub-freezing temperatures. As for when I was side sleeping, I managed to keep warm by leaving the bag flat and opening up the side zip just a tiny bit to let my face out. In general, I really like the weight and loft but side sleepers do have to compromise with this bag.

I write this review somewhat reluctantly, because I have many REI products that I love (especially the tents - my old model half-dome 2 is amazing) and it's a great company. The return policy alone lets me know that they are interested in customer satisfaction and having long-term relationships with their customers. This bag does not change that, but that said, this was worthy of a review. So, here goes my long review.... There are some significant problems with this bag. I actually just bought the bag during the anniversary sale a couple of days ago, and I was pretty optimistic. I liked the size, the weight, the temperature rating and the value. I decided to test it out up at Tahquitz meadow in SoCal and another spot nearby. Tahquitz is at about 8,000' and had a 36 low overnight. The nearby spot was warmer, probably 42 degrees (I didn't see the temp as my bag with keychain thermometer was not in the vestibule that night). Tahquitz meadow had some frost in the morning, with a very little bit of condensation inside the tent in the morning and a slight bit of frost on the outside in the morning. The next spot was quite dry and warmer. I'm 6.0', 190, for size reference, which is relevant. And I've used mummy bags for years with no issue. Conceptually, the bag is great. The underside is a waterproof/water repellent material with very little to no insulation (it would get squished down and useless anyway) and the top has down insulation where it is really needed. Awesome. But reduced to practice, the bag did not perform. The main reason for this is that there is not enough down or other insulation around the bottom edges. Basically, it is a perfectly aligned amount of down on the top that stretches just barely to the lower edges - but no further. So, what happens is, unless you are actually a mummy, or sleep akin to a dead person, any variation in your body position will cause the non-insulated areas on the bottom edge of the bag to be exposed to the air, or even worse, the ground off the edge of your sleeping pad. The result is very uncomfortable. It's drafty. Very drafty. I've never actually had this problem with a sleeping bag. But it's no fun. And while you may never actually get cold overall (the rating is pretty accurate I think), you will be in a constant battle against cold spots. And it's weird, I've never felt too confined in a mummy bag, but when every movement is punishable by cold spot, it becomes exceedingly confining. This problem is magnified for side sleepers. The bag is a little more confining than other mummy bags I have been in before to begin with (it's narrow), but because there is no real insulation on the bottom, you can't just flip sideways in the bag like an earthworm and expect your rear to be reasonably warm. Nope, if you flip the whole bag with you sideways, your hindquarters will be exposed with the non-insulated part of the bag and be quite chilly. So you end up having to carefully slither around inside of the bag to try to make sure the bottom of the bag stays on bottom if you want to stay warm. With a pretty narrow mummy bag, that's tough to do, much less while half-asleep, especially with no clear features delineating the top from the bottom (and at night in the dark on the inside of a sleeping bag, the only distinguishable feature is the zipper). And inevitably, your rear will get cold in the process. And then, if you have previously cinched the drawstrings around your face into a small opening to stay warm, and are finally positioned sideways, do you know where that opening/breathing hole ends up? Your ear. That's right, your ear. You will have a well-ventilated, freezing cold ear, and you will be breathing into the side of a bag. And the all-too-awkwardly positioned drawstrings will be dangling right in your earhole (better than in your eye I suppose). The innovation on this bag is really cool. I love the mix of materials, the weight, all of it. For a dead-to-the-world back-sleeper, this could possibly be the best bag ever (if you are that kind of sleeper, buy this bag now!). And with a few more inches of wrap-around down or other insulation coverage on the edge/bottom portion, it might be workable for medium-thrashers as well, especially if it is widened up a bit to accommodate movement in the bag. But as it is, if you move around much at all, beware, it will be ultra-ultra-ultra frustrating and uncomfortable. You may curse at length. Unfortunately, as a mummy bag, I don't think the concepts built into this bag really work. So - until it's fixed up a bit, I'm going to be returning this bag, and I will very likely be picking up a solid down quilt, where I think much of the inspiration for this design probably derived. Great attempt on this bag, but I don't think it's quite there yet.