The McKinley is a "heavy-duty" oversized hooded rectangle bag. It uses a 2-layer offset construction to eliminate cold spots. The McKinley series uses 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's sleep. 4853458 McKinley 0deg 4900027 Rectangle Liner - PolyCotton 4900029 Rectangle Liner - Brushed Polyester