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Sidewinder 20°
Sidewinder 20°
Sidewinder 20°
Sidewinder 20°
Sidewinder 20°
Sidewinder 20°
Sidewinder 20°
Big Agnes

Sidewinder 20°

Traditional Mummy Bag Optimized for Side Sleepers

Specifically designed for the 60%+ of people who sleep on their sides, the second generation of patented Sidewinder technology delivers warmth, comfort, and ease of use in any position. Built with body-mapped insulation, it provides warmth where you need it most while adding cushioning at the hips and shoulders to reduce pressure points.

The Sidewinder is a side sleeper’s dream—engineered to move with you as you roll from one side to the other, seamlessly adapting from one adventure to the next.
U.S. Patent 11957260 B2

Features

  • Second-generation side sleeper design with a technical fit that moves with you
  • Optimized profile and thermally efficient footbox shaped for side sleeping position
  • Down insulation with water-repellent finish for lofty warmth
  • Strategically placed synthetic insulation for cushioning at knees, hips, and shoulders
  • Close-fitting, jacket-style hood for warmth without restricting movement
  • Pillow Barn system:
    • Stretch mesh keeps pillow in place
    • Interior access from either side for easy adjustment
  • Smooth, anti-snag locking zipper with no-draft zipper garage
  • Long, ambidextrous zipper for flexible use
  • Low-profile internal cordlock for easy hood adjustment without unzipping
  • Insulated tube along hood opening to seal out drafts
  • Storage sack and stuff sack included

Specs

  • Total Weight: 2 lb 4 oz
  • ISO Comfort: 30°F
  • ISO Limit: 19°F
  • Fill Weight: 14 oz Down + 6 oz Synthetic
  • Compressed Size: 9.5" x 8"
  • Stuff Sack Size: 14L | 8" x 17.5"
  • Max User Height: 5'6"
  • Recommended Pad: Works with any pad size or style
  • Shoulder Girth: 58"
  • Hip Girth: 52"
  • Foot Girth: 33"

Materials & Construction

  • Shell: Recycled polyester ripstop with water-repellent finish (no intentionally added PFAS)
  • Lining: Recycled polyester taffeta with water-repellent finish (no intentionally added PFAS)
  • Primary Insulation: 650 fill DownTek™ (PFC-free, bluesign® certified water-repellent chemistry)
  • Body-Mapped Insulation: FireLine™ ECO synthetic (100% post-consumer recycled polyester)
    • Low-denier fibers for high loft, compressibility, durability, and warmth efficiency

Down Sleeping Bag Care

Storage

  • Store uncompressed (hang if possible or use included mesh storage sack)
  • Keep in a cool, dry place away from heat sources

Cleaning

  • Machine wash without an agitator
  • Use oversized machines if needed (laundromat recommended for large bags)
  • Wash on warm, gentle cycle
  • Use down-specific soap (e.g., Nikwax Down Wash Direct)
  • Rinse twice
  • Tumble dry low with clean tennis balls
  • Finish drying on high heat in 5-minute intervals to restore loft
    • Allow cooling between intervals to prevent damage

Do Not:

  • Use fabric softeners
  • Bleach
  • Iron
  • Dry clean

Repairs & Warranty

  • Guaranteed against manufacturing and material defects
  • Not covered:
    • Normal wear and tear
    • Owner modifications
    • Misuse or accidents
    • Use outside intended purpose
  • Repairs may be available at a reasonable cost
  • Returned gear must be clean and free of debris
Sidewinder 20°
Sidewinder 20° Sale price$329.95 USD