The men's Kyan™ ultralight backpacking mummy has set a stake in the ground, defining the high-end premium synthetic sleeping bag. Our patent-pending FeatherCore™ construction, made with premium Primaloft® insulation, is a revolution in insulation, offering ultra-compressibility without sacrificing warmth. This completely new take on insulation construction packs down significantly smaller, providing all the benefits of synthetic insulation at the same pack size as 650FP down. Coupled with an aggressive shape and a full suite of features, these bags are the new ultralight go-to.