Warm enough for backpacking spring through fall, the women's REI Co-op Zephyr 20 sleeping bag is our top synthetic design—light, compressible and cozy, with construction that maximizes comfort.
Fill
Polyester fibers
Temperature Rating (F)
20 degrees (F)
- With an International Organization for Standardization (ISO) T-Comfort rating of 22°F and T-Limit rating of 9°F, this bag is suitable for 3-season use
- Women-specific design offers more room in hips and slightly narrower shoulder girth for the best fit and thermal efficiency
- Synthetic polyester insulation is durable and highly compressible; the fill also retains some insulating ability if it gets wet
- Shingle construction with overlapping layers distributes insulation evenly and prevents cold spots
- Mummy shape is thermally efficient, yet roomy enough from shoulder to knee to ensure sleeping comfort
- Trapezoidal footbox gives room to wiggle toes and the baffle in the toe box holds extra insulation in place to help keep feet warm
- Hood, insulated muffler and full-length zipper draft tube keep warmth in and cold out
- New zipper cover and internal antisnag strip combine for easy zipping
- Stash pocket under collar holds small essentials
- Differentiated drawcords allow quick hood and neck adjustments in the dark
- Ripstop polyester shell offers durability with abrasion- and tear-resistance for years of use
- Nylon stuff sack and polyester storage bag are included
- REI is Climate Neutral Certified; as we work to actively reduce our footprint, we measure annual carbon emissions and purchase an equivalent amount of verified carbon credits
- Contains materials that meet the bluesign® criteria
Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Our backpacking bags are rated for temperature according to an independent testing protocol: International Organization for Standardization (ISO) 23537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.
Each bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
View the REI Co-op Zephyr Product LineView all REI Co-op Backpacking Sleeping BagsEach bag then gets 2 ratings: the Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. For REI Co-op brand nongendered sleeping bags, we provide an overall temperature rating that falls between the Comfort and Lower Limit ratings.
| Best Use | Backpacking |
|---|---|
| Tested Lower Limit | 9 degrees (F) - ISO |
| Tested Comfort | 22 degrees (F) - ISO |
| Temperature Rating (F) | 20 degrees (F) |
| Temperature Rating (C) | -6 degrees (C) |
| Shell | Ripstop polyester (bluesign® approved) |
| Zipper Location | Right |
| Insulation Type | Synthetic |
| Fill | Polyester fibers |
| Lining | Nylon taffeta (bluesign® approved) |
| Sleeping Bag Shape | Mummy |
| Stuff Sack Size | 7.25 x 16.5 inches |
| Stuff Sack Volume | 10 liters |
| Gender | Women's |
| Sustainability | Contains materials that meet the bluesign® criteria From a Climate Neutral Certified brand |