The people at Western Mountaineering are pretty proud of their Caribou MF 35 Degree Down Sleeping Bag, with its MicroLite XP breathable microfiber yarn that's densely woven to create a high thread-count material that naturally fends off moisture. Weighing in at a mere pound and a quarter, this is Western Mountaineering's lightest-weight Microfiber Series bag, ideal for summers spent hiking in the mountains or touring the country on two wheels.