I didn't freeze even when it was about -20 degrees below zero. The glow-in-the-dark zipper puller is a plus. Zipper pocket too small. There is no suitable place for the phone.
Verified buyerJanne L.

Neutrino 800 is the warmest Neutrino-series sleeping bag. When you need a really good warmth-to-weight ratio, this is it!
This is the new 2019 model of Neutrino 800. The updated design has chevron-shaped baffles to ensure the down is held over the center of the body and prevents down migration, while the trapezoidal chambers eliminate cold spots.
The limit temperature for this bag is -22°C, making for great comfort in truly cold conditions. Rab does not give extreme temperatures for their warmest winter bags as the EN tests for sleeping bags don’t accurately represent real-life performance in extremely cold conditions.