The Western Mountaineering Kodiak MF 0 Degree Down Sleeping Bag is a backpacker's dream. This mummy bag uses lightweight 30-ounce 850+ down fill insulation that provides a full 7 inches of loft. While the down brings the warmth, the sleeping bag weighs in at a modest 2lb 15 oz (regular size) so it isn't also bringing the weight. Its MicroLite XP shell is surprisingly durable despite its lightweight appeal. It's also very breathable and highly water-resistant so we get a restful recovery during the cold nights of our backpacking adventures without carrying around excess weight.