The McKinley is a "heavy duty" oversized hooded rectangle bag. It uses a 2-layer offset construction to eliminate cold spots. The Yukon series use Techloft Insulation. Techloft Insulation consists of multi-hole staple-length micro-denier fibers that have a siliconized finish for maximum insulation, loft, and compactness. It will keep you toasty on those colder nights when you"d prefer to have more "wiggle room" than you get with your mummy bag. The contoured hood also helps keep you warmer and keeps your warmth sealed in. For transporting, we include a compression stuff sack and roll-up straps. This is a great hunting bag for those frigid nights when you want a good night sleep.