Big Agnes Sidewinder SL 20 Sleeping Bag - 650 DownTek (Petite, Women's)

Meet the Sidewinder SL 20: Designed for Side Sleepers

If you sleep on your side, you know how crucial it is to have a bag that moves with you and keeps warmth where you need it. The Big Agnes Sidewinder SL 20 is engineered specifically for side sleepers, with a body-mapped design that reduces pressure points while maintaining loft. This approach helps you settle in comfortably, whether you’re switching from one side to the other in the night or settling into a single position after a day on the trail.

Smart warmth for real-life camping

The bag combines DownTek insulation with a thoughtful interior map. The primary fill is 650-fill DownTek, which repels moisture while preserving warmth. In the hips and feet, a synthetic FireLine ECO insulation—made from 100% post-consumer recycled polyester—helps minimize cold spots and pressure points without adding bulk. The result is lofty warmth that stays responsive to motion and body heat, with a touch more protection where you tend to feel chilly.

• Body mapped insulation targets warmth to where you need it most, while reducing pressure points for side sleepers.
• 650 fill DownTek main fill plus FireLine ECO synthetic in key zones balances loft, warmth, and durability.
• Jacket-style hood is close-fitting and moves with you; the insulated tube cinches to seal drafts.
• Pillow Barn keeps your pillow in place with interior access from either side for easy adjustment.
• Long ambidextrous zipper with anti-snag design prevents drafts and snagging while changing positions.
• Bluesign Certified water-repellent treatment with PFOA/PFOS-free chemistry adds weather resistance.

Women-specific shaping with a gentler taper from shoulders to hips helps reduce cold spots, delivering warmth where it counts. The Sidewinder SL balances performance with comfort, so you stay cozy from the moment your head touches the hood to the last night you crawl out of your tent.

Key specs and everyday practicality

• Weight: 2 lb 7 oz; packed size: 7 x 8 inches
• Fits campers up to 5’5” / 165 cm; shoulder girth 56”, hip 54”, footbox 31”
• Primary fill: 650 fill DownTek; body mapped FireLine ECO synthetic insulation in hips/feet
• Bluesign Certified water-repellent finish; no PFAS or PFOS
• Includes storage sack and stuff sack; hang loops for drying

With its thoughtful features—including a dedicated hood, an anti-snag zipper, and a design that travels well between camps—this bag is built to transition from one adventure to the next. While it offers warmth and comfort in a compact package, it’s important to remember that performance depends on conditions and personal comfort preferences. Consider this bag as a capable partner for side-sleeping camping experiences that lean toward reliable warmth and targeted support.