Therm-a-Rest Saros 0F/-18C Sleeping BagStay warm and toasty all winter in this sleeping bag. When the weather gets frigid and the forecast looks damp, the Saros 0F 18C is equipped to keep you resting better. The Saros uses our eraLoft synthetic insulation, which is quick drying and weather resistant, making it ideal for backpacking and mountaineering in wet weather from spring to fall. The fit of the bag has been perfected in our onsite cold chamber to create our W. A. R. M. fit that