The Katabatic Gear Sawatch 15 is an ultralight, high-powered furnace of a sleeping bag. It's a warmer version of our highest rated backpacking bag, the Katabatic Gear Palisade. It does take a while to order and receive this from its small Colorado manufacturer. We find it to be well worth the wait.
We recommend the Sawatch to anyone that wants a substantially warmer bag for below freezing nights in the spring, fall, or if used with a down jacket.