Big Agnes Sidewinder SL 20 Sleeping Bag - Women's
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Ergonomically designed for rolling side sleepers, the Big Agnes Sidewinder SL 20 women's sleeping bag keeps you cozy and comfortable through every roll, turn and flop for a more restful night.
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Key Details
- Ergonomically contoured, technical fit patterned to move with you as you roll from one side to the other, while ensuring warmth and comfort as you settle into position
- 650-fill-power DownTekâ„¢ insulation offers lofty warmth throughout with a PFC-free water repellent finish to keep you dry, even if when wet
- Body-mapped FireLineâ„¢ ECO synthetic insulation alleviates pressure points at the hips and feet while retaining optimized warmth
- Made from post-consumer recycled polyester, FireLine ECO maintains high loft, compressibility and durability with excellent weight-to-warmth ratio
- Ripstop shell fabric and smooth, polyester taffeta lining are treated with a PFC-free water repellent finish to help keep you dry and warm
- Jacket-style hood keeps insulation close around you without sacrificing mobility
- Stretchy mesh Pillow Barn built into the hood keeps your pillow in place; interior access from either side allows for easy adjustments
- Specially designed footbox mimics the shape and position of your feet while lying on your side for an optimized fit and thermal efficiency
- Smooth, antisnag locking zipper and zipper garage ensures no drafty cold spots
- Low-profile cordlock hood and insulated draft tube allow easy one-handed operation to seal out cold drafts
- Exterior loops allow you to easily hang dry or store bag when not in use
- Compatible with virtually every type and size of sleeping pad (not included)
- Includes storage sack and stuff sack for compact packing
Imported.
View all Big Agnes Backpacking Sleeping Bags| Best Use | Backpacking |
|---|---|
| Temperature Rating (F) | 20 degrees (F) |
| Temperature Rating (C) | -7 degrees (C) |
| Ultralight | Yes |
| Shell | Ripstop nylon |
| Zipper Location | Front |
| Insulation Type | Down / Synthetic Blend |
| Water-Resistant Down | Yes |
| Fill | 650-fill-power DownTek/FireLine ECO |
| Sleeping Capacity | 1-person |
| Lining | Polyester taffeta |
| Sleeping Bag Shape | Mummy |
| Stuff Sack Size | 8 x 17.5 inches |
| Stuff Sack Volume | 14.4 liters |
| Gender | Women's |
| Sustainability | Contains recycled materials Down certified to the Responsible Down Standard (RDS) |
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Most Helpful Favorable Review
Most Helpful Critical Review
Comfy bag for a restless side sleeper
I purchased this bag for a recent camping trip and was very pleased with it. I am a side sleeper and tend to toss and turn when sleeping outside my bed. The bag easily moved with me. I also found it very soft and comfortable and with the stuff sack was easily able to get it to fit in my duffle bag with my other stuff. Admittedly was not in temperatures anywhere near 20, probably somewhere in the 40s instead, but I found it more than warm enough while sleeping in a t-shirt and regular pajama pants. Somenights I even opened the top part to cool down some, something it made it easy to do
Comfortable but looses down
I was really excited about this bag, as I constantly roll from side to side and fight with the zipper on a regular bag. The sidewinder was really warm, comfy, soft fabric, and a great loose fit as advertised. I haven't slept as comfortably in quite a while! Unfortunately the bag looses down like a sieve. As my old bag (20 years old) is thin and cold now from loosing down in this same way, I'm not in a hurry to repeat the experience, especially with a brand-new bag. I will be returning it.
Luxurious!
Favorite bag ever! Nice & lightweight, but plenty warm (coldest camp was upper 20s so far). Soft and silky material feels so nice on my skin. The zipper on top seems so simple, yet so revolutionary to me! Very comfortable for someone who flips from side-to-side several times throughout the night. Plenty of room to curl my knees up towards my chest, I never feel constricted. The colors are pleasing to me eyes, too. I have recommended this bag to anyone who will listen! So very satisfied with this purchase.
Great design but not a 20 degree bag
I absolutely love how this bag is designed - the pillow pocket, front zipper, fluff, weight - all of it is great. Unfortunately, it is not a 20 degree bag. I camp/backpack a lot and took this out on my last weeklong trip. The lows only got into the upper 40s and I was shivering. I never shiver at that temperature in my quilt or other bags. I love the design so much that I hate to return the bag but I rarely camp at temperatures above 50 so this bag ends up being unusable for me.
Comfy but cold
I’ve had this sleeping bag for a year now and am considering upgrading. What I love about the bag: Lightweight, packs down easily Comfortable and roomy enough to move around in The sleeping bag barn makes it easy to side sleep and still use a pillow What I don’t like about the bag: Even in the summer/late fall this bag was too cold at times. I’m not sure how it’s rated to 20 degrees but I get cold in it when it hits about 40. It loses a lot of feathers- even after one use I noticed it shed feathers and continues to do so.
Very pleasantly surprised
So happy with this bag! Bought it for a trip to Alaska in March (not outdoor sleeping, but likely on school or other public building floors) and as a side sleeper interested in that option. Am "petite" at 5'4" but opted for the regular size due to torso fit concerns (curvy especially around mid-section). Have been extremely ticked off by the lack of comfortable plus-size options in light weight cold weather gear (looking right at you, Patagonia, and also you, Columbia), so low expectations. Tried it out on the floor yesterday evening - incredibly cozy, easy to get in and zip up, nice amount of room around arms and torso, great fitting hood and face opening, easy to flip from side to side, nice fit around my feet, comfortable level of padding and warmth. Not embarrassed to admit that I had a very sweet little nap for myself! Looking forward to using it in the field! Bonus - truly love the colors and the stash and pack bags provided.
Comfortable But Cold
I found this bag very comfortable however no way is it a 20 degree bag. I was out for several days with nights in the low 40's, it was not quite warm enough for me, I had to throw my down jacket on top to stay warm. I usually warm up easily in other 20 to 30 degree bags.
Nice sleeping bag
Sleeping bag is really nice, but I got the petite, thinking it's 2 inches longer than I am, but my camping pillow popped out the bag on top, and my feet were squished into the bottom. I'll be reordering the regular size.
comfy but loses feathers
It's much easier to turn as a side sleeper, but I keep finding feathers everywhere. Also on a recent car camping trip, I was freezing the first night even though I had 3 layers on top, heavy socks, and heavy sweatpants. The low was in the lower 30s. This may have been impacted by the larger air mattress I used on that trip, but I don't think this should be rated for 20F. I've used it on backpacking trips that were warmer (40s) and that was fine.
Needs some work
Great idea that fell short. I am a side sleeper, but not just one side. This bag was warm, but didn’t allow me to flip to my other side to sleep. Had to return. Bought the same brand because the bag is well-made. Just not the sidewinder.

