Big Agnes Sidewinder 20

The Big Agnes Sidewinder 20 is a specialized solution for the 60% of adventurers who find traditional mummy bags restrictive. Designed specifically for side sleepers, this second-generation bag prioritizes ergonomic comfort and freedom of movement throughout the night. It utilizes a sophisticated hybrid insulation approach: high-loft, water-repellent down provides exceptional warmth-to-weight throughout the body, while strategically placed synthetic insulation offers crucial cushioning at the knees, hips, and shoulders. This body-mapped configuration targets common pressure points, ensuring a restful sleep whether you are on a multi-day trek or a weekend camping trip. With a comfort rating of -1°C and a limit of -7°C, it is an ideal two-season companion for mountain adventures where temperature fluctuations are expected and recovery is paramount.

Performance is driven by the Sidewinder’s technical fit, which is patterned to follow your body as you roll, preventing that restrictive "tangled bag" sensation. The optimized profile includes a thermally efficient footbox shaped for side-lying postures and a jacket-style hood that maintains a close seal without feeling claustrophobic. A standout feature is the integrated ‘Pillow Barn’—a stretch-mesh pocket that keeps your pillow securely centered all night with easy access from either side. For temperature regulation, the bag utilizes a long, ambidextrous anti-snag zipper with a draft-proof garage to eliminate cold spots. Internal, low-profile cordlocks allow you to cinch the hood tight without unzipping, keeping the heat effectively locked in. Supplied with both storage and stuff sacks, the Sidewinder 20 is a feature-rich, refined choice for demanding backcountry sleepers.

Big Agnes Sidewinder 20 Features

• Specifically designed for people who sleep on their sides
• Shell: nylon ripstop featuring a PFC-free water repellent finish
• Lining: polyester taffeta featuring a PFC-free water repellent finish
• 650 fill power DownTek down
• FireLine ECO Synthetic Insulation, 100% post-consumer recycled polyester
• Quick zip with anti-snag locking zipper with no draft zipper garage
• Easily adjust hood without unzipping using low-profile internal cordlock access
• Storage sack stuff sack included