Big Agnes Women's Sidewinder SL 20°

The Big Agnes Women's Sidewinder SL 20° takes the side-sleeper-focused Sidewinder cut and cuts weight, dropping to 1104 g by pairing 650-fill hydrophobic down with FireLine ECO synthetic insulation mapped to the hips and feet — the areas that compress most and lose loft when sleeping on your side. Unlike most bags in this lineup, its -1°C comfort / -7°C limit rating is EN ISO 23537 lab-tested rather than manufacturer-estimated, which generally makes it a more directly comparable figure. The 3/4-length, two-way center zipper and adjustable fitted hood with draft collar keep the design efficient rather than full-featured — there's no draft tube or storage sack included, trade-offs typical of the lighter SL line versus the heavier Camp versions. RDS-certified, PFC-free down adds a traceability angle for buyers who care about the down's sourcing. At just over a kilogram and sized to 165 cm, this suits backpackers who sleep on their side and want a genuine weight reduction over the Sidewinder Camp 20° without giving up the rotating cocoon fit.