The Redwood is a "heavy-duty" oversized rectangle bag. The Redwood 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. The TechLoft insulation will keep you warm and toasty on those colder nights when you'd prefer to have more "wiggle room" than you get with your mummy bag. It uses a 2-layer offset construction to eliminate cold spots. For transporting, we include three webbing straps with quick-release buckles that keep your "rolled-up bag" secure. Two Redwood -10deg bags can be zipped together to create a double bag. 4073314 Redwood -10deg 4900027 Rectangle Liner - PolyCotton 4900029 Rectangle Liner - Brushed Polyester