I have one from Cabelas. Not sure if they sell this particular bag anymore. I believe its a -20 bag. It's a great basecamp/truck camp bag.
That said, we spent a week a few years back on an early NOV deer hunt when temps got into the -22 range overnight. I'm a cold sleeper anyway but had to layer up a bit inside the bag and was comfortable enough once I warmed the bag up.
They are great for early season hunts when you can just leave the zipper open, mid season hunts where temps still aren't overly cold and amazing for wall tent camps.
http://www.huntingbc.ca/photos/data/500/truck19.jpg