If you've ever wished for a less-constrictive sleeping bag that keeps you comfortable in a variety of cool-to-warm conditions, the Trek may become your go-to bag. The Free-Flow Zip system allows you to open the bag sequentially for ventilation up to the point where it is opened flat as a quilt - you can even secure the snaps around your shoulders, open the footbox zipper and 'wear' the Trek around camp Design and Details: The flexibility of the Free-Flow Zip system plus the comfort of the spacious cut makes the Trek a natural choice for close-to-home campers and long-distance travellers alike RDS-certified, 650+ fillpower duck down with a non-PFAS Ultra-Dry Down treatment to stay drier in damp conditions Includes a recycled 20D polyester shell with a non-PFAS DWR finish blocks wind and moisture, while the polyester liner provides pure comfort Free-Flow Zip System offers great temperature regulation and multiple sleeping bag configurations Tapered-rectangular fit is designed for spacious comfort when you're camping or traveling Sea to Summit Guarantee is offered for the Lifetime of this product