Nunatak Equipment - Nano Bag (formerly Z-Strugi)

Not saying Jan is the ultimate authority but this is directly from one of his product pages: *Sastrugi zipper-less bag vs Strugi Quilt:* *Comparing the two shows that weight savings are minimal. A person needing the 59" wide Sastrugi bag would choose the 56" or 53" Strugi Quilt, but the added hardware of the quilt (ETC, straps, snaps and buckles) almost make up for the difference.* *In environments with consistent night time temperatures, say western mountains at altitude with nearly guaranteed cool nights, the Sastrugi makes sense: draft free, easy to use, simple, affordable.* *On the other hand anyone gearing up for a streak of major thru hikes should consider a quilt. Thousands of miles and hundreds of days along changing seasons and environments require the adaptability of a modern well designed quilt.* The hoodless bag is also ~$100 cheaper. No brainer for my use case and wallet.

All the Sastrugi hoodless/zipperless bags as shipped have the same temp rating (ie loft) all the way around; and top to bottom. The user can if they want shift the fill to one side or another - not really something I bother with personally but with the continuous baffles it's doable. During use, combined with a laissez faire attitude towards down position maintenance, the fill can move away from areas as we all know.

It's worth it. I bought a Flex 22 duck down and every humid night it stank like wet animal. Drove me nuts and I sold it and went with Nunatak goose down. I think goose down is worth every penny more just for the lack of smell benefits.