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. 650+ fillpower duck down with a non-PFAS Ultra-Dry Down treatment keep you insulated in damper conditions. Slip an Aeros Pillow into the hood and enjoy a great night's sleep - wherever your travels take you. Features 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