At present, I own seven sleeping bags. Which is a bit ridiculous, I know, but truth be told, the number would be even higher had I not given a couple away over the past few years. My all-time favorite (so far) is a $150 bag called the Synthesis 20, from Sierra Designs. But it’s also surprisingly similar to one that costs just $30, the Sportneer 20F Ultralight Mummy Bag.
First, let’s discuss two attributes of the Synthesis that are, as far as I know, unique to Sierra Designs’ bags, and which happen to be the reasons it’s my favorite. The Synthesis 20, like many bags from the brand, features a non-zippered foot vent that allows you to slip your feet out of the bottom of the bag. This makes temperature regulation much easier in warmer conditions, quickly letting air flow into the bag and releasing excess heat. On cold nights, you slip your feet down past the vent, which is pressed shut and keeps the warmth inside.
Then, at the other end of the bag, you will find a dual-zippered design. There is a zipper running half the length of the sack on one side, and a quarter of the length on the other, and when used in concert, these twin zippers allow you to fold down the top of the sleeping bag, much like you would a blanket in your bed. This again allows for great temperature regulation, and also makes it easier to get in and out of the bag and more comfortable as you hang around reading, chatting, or studying a map of the next day’s route.
Though perhaps untouchable in these respects, the Synthesis still has a lot in common with the Ultralight Mummy. Let’s start with their temperature ratings. As the name suggests, the Sportneer 20F has a 20-degree limit, and it’s rated for comfort down to 30 degrees. (The limit rating is about safety, so don’t mess around there, folks.) The Synthesis 20? You guessed it: also a 20-degree, and in this case, an oddly specific 31-degree comfort rating. Full disclosure, I’ve never used either bag in temps much below 50 degrees, but I can say I was always plenty warm. Like, foot-vent warm.
Next, in weight, the bags are almost identical at about two pounds each. Packed down, they are both about the size of a large shoebox (and a bit large for long excursions or technical climbs, for the record, but perfect for weekend treks or car camping). And for the record, I’m 6’2” and I fit in both bags with ease, even with my head tucked into the hood, which can be cinched tight on both sacks.
Again, I love the double zippers and foot vent on the Synthesis. But again, I have amassed many sleeping bags in my time: a queen-size bag my wife and I can share; a kid-size sleeping bag for the kids; a big, flannel-lined bag that’s perfect for guests when the guest room itself is already occupied. I’ve even bought myself one in the over-$200 range. So I feel confident in saying that you will very much get your money’s worth with the Sportneer, too.
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