Women's Greystone 20°

The mummy shape really does keep the warmth in, and I stayed comfortable right down to the low 20s on a chilly weekend trip. It packs down small enough to strap to the bottom of my pack without weighing me down.

Took this on a three-night backpacking trip and it kept me comfortably warm down to about 25 degrees. Packs down smaller than my old bag and the mummy shape really cuts the drafts around my shoulders.

I was skeptical a lightweight bag could keep me warm at 20°, but I slept comfortably in just a base layer. The mummy shape really cuts down on dead space, and it packs down small enough to strap to the outside of my pack.