Sastrugi
New product
Zipperless bag. Simple, light and no nonsense.
If you need this you will know.
High quality 900 fill applied in a generous quantity, cord at the top, light fabrics, no inward taper until hips. Pro tip: down can be shuffled from topside to undersize, or vice versa.
Perfect inside a synthetic over-bag for gnar conditions.
Concerned about getting in and out of a zipperless bag, and hot weather venting? Look elsewhere.
Sastrugi; snow eroded by wind into ridges. A skier's nightmare.
The Perfect Bag - NO DRAFTS!
https://imgur.com/gallery/eTGWaKQ pics of my Sastrugi.
I got a 28F sastrugi w/ overfill and have used it for ~6 nights without baselayers (male sleeper). The highest night was 48F which was almost too hot for this bag, but it worked okay with leaving the top open. You can also just drape the whole bag over you like a blanket or roll it down halfway on warmer nights. Lowest night was 36F which was really cozy.
I was concerned about the entrance/exit with the zipperless design, but it's not really a big deal, and it eliminates the draft, so I'm happy with it!
It would pair nicely with an apex/alpha quilt (or bivy) for a wide range of use.
Also of note - I'm 5'10 170lb male and got the 70"/62"/40" dimensions and it was roomy! Especially in the torso region, you can fit a huge parka in if you want!