Traditionally, all of the lightest weight bags are made with the extremely light ripstop nylons. We created our Caribou MF to be lightweight, durable, and comfortable by using our lightweight Microfiber material. This 1 lb. 4 oz. mummy bag has a full length zipper and is cut wider than average for broader shoulders and a more comfortable fit. With its breathable, water resistant outer shell, the Caribou MF is a great lightweight summer bag and a perfect choice for AT hikers.