TETON Sports LEEF Ultralight Mummy Sleeping Bag Perfect for Backpacking, Hiking, and Camping; 3-4 Season Mummy Bag; Free Stuff Sack Included

For the price, no other sleeping bag comes close to the Teton Sports Leef 0-degree sleeping bag. I'm 6-foot and broad-shouldered, and found the smaller Teton Sports 20-degree Trailhead bag to be much too narrow in the shoulders to be used as anything other than a makeshift quilt. To its credit, the Trailhead bag kept me warm, even unzipped for use as a quilt, when temperatures dropped to the middle and lower 40s ... but I can use the Leef fully zipped and there's still plenty of headroom to draw the hood tight. Like all mummy bags, the Leef is confining, but as a side-sleeper it still worked for me. I couldn't roll over WITHIN the bag, but it was easy to turn myself AND the bag to the side. Like the Trailhead, the inner fabric of the Leef is a brushed material that is soft against the skin; it never feels wet, slippery or slick. And, as you'd expect, this bag feels considerably warmer as suggested by the lower temperature rating. About that rating: Like almost all sleeping bag companies, Teton Sports' temperature ratings should be considered "extreme" or "survival" ratings -- not "comfort" ratings. To figure out the temperature at which a bag will still keep you comfortable, the rule of thumb is to add 25 to 30 degrees to the advertised rating. So, with the Leef 0-degree bag, I can expect to get a decent night's sleep at 30 degrees. (To Teton Sports' credit, they tell customers upfront to be mindful of the fact that their temperature ratings are "extreme" level, not "comfort" level.)Other things to keep in mind about this bag:THE ZIPPERS -- There are two on one side of the bag, so you can leave one at the bottom and then zip the other one all the way to the top, and then, if you get warm, you can open that bottom zipper a bit for some venting near your feet. The zippers work well, and snags aren't an issue. It's odd that they placed the zippers on the left side of the bag, however, since it makes zipping things up a bit more awkward for right-handed people.THE COMPRESSION BAG: It seems durable and perfectly sized for the bag, so feeding the bag back into it is easy enough. The fully attached compression straps do a good job of minimizing the overall size.OVERALL SIZE: Even in its compression bag, the Leef is still about 50% to 75% larger than the Trailhead bag in its stuff-sack. This means it won't fit into the sleeping bag compartment at the bottom of the popular Teton Sports Scout 3400 backpack -- but of course that pack allows you to unzip that compartment so it's not walled off from the rest of the backpack. Simply unzip that compartment and then drop (or rather, wedge) the Leef into the bottom of the Scout 3400 from the top opening of the backpack. You'll see it eats up close to half the 3400's available space, so if you're upgrading from the Trailhead bag to the much larger Leef, you may also want to upgrade your pack from the Scout 3400, which has a 55-liter capacity, to the Teton Sports Explorer bag, which comes in both a 65-liter and a 75-liter size. >>>UPDATE: The long version of the Leef sleeping bag is far too big to fit inside the sleeping bag compartment of even the 75-liter Explorer backpack, which is a real disappointment. I assumed Teton Sports would have upsized the sleeping bag compartment of its larger backpacks so they would accommodate the company's own larger-sized sleeping bags -- but they did not. I will still be able to haul the Leef inside my Explorer backpack by opening up the segregated compartment and inserting and removing the Leef from the top of the Explorer, but of course that means I'll have to take out EVERYTHING in the pack each time I need to access or re-pack the Leef. That's not something anyone would want to do in the rain...

To get to the point, I debuted this bag on a camping trip in early December 2022 in the NC Appalachians near Banner Elk in rainy conditions and one of the nights it got down to 33 degrees... I wore literally nothing in the bag the first night just to test its conditions and it really did keep me warm!An issue is that air comes in through the facial hole in the mummy bags so you'll want to find a way to block that without suffocating, but it's better than the alternative. Teton Sports is a great company that, as you can see, is actually active on this page answering questions, I'd definitely listen to them that 0 F degrees actually means you will be kept ALIVE in the bag down to this temperature, but it will begin to be an uncomfortable night at 20 F degrees instead, so read '0' more as '20'.If you don't live in some extreme environment, this is a great bag. Anyone in the southeastern US should be just fine with it. If you bundle up inside it, you're even better off.I also want to say that this thing is more comfortable than my bed. When I entered it the first time, it was like entering some kind of advanced spa. I felt more relaxed than I had ever before, but you're going to get really hot in there if you aren't in the cold! If you get cold easily, perfect. If you stay warm, you'll probably think its even more comfortable in winter weather, which it really can hold up to.My tent got water inside it somehow during those nights last month (it's not supposed to) and you couldn't help but have the bag touch the water... unless you're really tall (like, REALLY tall), you aren't going to take up this whole bag, especially when curled up in the winter weather, so it wasn't an issue. The water didn't soak the whole bag or spread in it, but then again it was so cold maybe I couldn't tell.The only con I would say is that this kind of polyester gets cold very easily, so entering this bag in under 40 degree temperatures is going to feel horrible for about a minute but it warms up extremely fast. I was amazed, inside the bag, reaching out to touch the outside where the bag's surface felt so cold but inside it it was very warm; this thing retains heat very well. I wish they'd make a version of this bag in some kind of hybrid cotton and in warmer colors, you feel like you're entering an alien pod in these colors, but they are really cool to look at and the green exposes any stains or debris in the bag while the external black makes it harder to find stains or issues. The dirt from the wet parts of the tent dried to the bag and wiped off easily, also a nice feature, the bag 'wicks' debris off its smooth surface quite easily.The manufacturer and label claims you can't wash the bag and it voids warranty if you do... that last part might be a problem, but you can absolutely wash the bag. I wouldn't do so OFTEN, considering I did with my Teton Sports camp pillow and it made a hole in the pillow, but you can do it... the idea that you just let your bag air out/stay dirty or wash it by hand is pretty absorbs, no one wants to be doing that. On the road trip, I opened the bag and let it air out and it didn't really smell anymore, though the smoke scent is pretty inescapable even after washing it.