User Review: The North Face Dark Star -40
Fill: Polarguard Delta
Temperature Rating: -40
Weight: 5 lbs.
Price Paid: $275
The good news is that I didn't freeze to death. The bad news is that this bag is nowhere near a -40 degree bag.
You can sleep in it when it's zero out but you better where extra socks, pants, turtleneck, etc.
Seriously, it was a disappointment and I doubt I'll try another NF bag because of it.