REI Co-op
REI Co-op Trailmade 20 Sleeping Bag
$100Cheaper
Best Sleeping Bags · head-to-head
REI Co-op Trailmade 20 Sleeping Bag vs Sidewinder SL 20 Mummy Sleeping Bag
A sourced, side-by-side comparison. REI Co-op Trailmade 20 Sleeping Bag is cheaper at $100. Every spec and price links to its source.
Big Agnes
Sidewinder SL 20 Mummy Sleeping Bag
$199.96
Which is better: the REI Co-op Trailmade 20 Sleeping Bag or Sidewinder SL 20 Mummy Sleeping Bag?
The Sidewinder SL 20 Mummy Sleeping Bag wins 1 of the 1 specs we compare head to head; the other wins 0. The REI Co-op Trailmade 20 Sleeping Bag is the cheaper at $100. Get the Sidewinder SL 20 Mummy Sleeping Bag for the stronger spec sheet, the REI Co-op Trailmade 20 Sleeping Bag to spend less.
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Full spec sheet
✓ marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.
| Spec | REI Co-op Trailmade 20 Sleeping Bag | Sidewinder SL 20 Mummy Sleeping Bag |
|---|---|---|
| US price | $100 | $199.96 |
| Brand | REI Co-op | Big Agnes |
| Released | — | — |
| Temperature rating f | 21 | 20 |
| Insulation type | synthetic | down |
| Fill power | — | 650 |
| Shape | mummy | mummy |
| Packed weight (lb) | 3.29 | 2.25 |
| Packed size | 10 x 13 in | 6.5 x 8 in |
| Zipper side | — | center |
| Product note | Replaced the discontinued Trailbreak 20; recycled synthetic insulation; ISO Lower Limit 21F, Comfort 31F | 650-fill DownTek hydrophobic down with body-mapped FireLine ECO synthetic at pressure points; designed for side sleepers; center ambidextrous zipper |
Sources — REI Co-op Trailmade 20 Sleeping Bag: rei.com (verified 2026-06-20). Sidewinder SL 20 Mummy Sleeping Bag: bigagnes.com (verified 2026-06-20).
What's the difference between the REI Co-op Trailmade 20 Sleeping Bag and Sidewinder SL 20 Mummy Sleeping Bag?
Where the two actually differ on the specs we track (5 of 8). Matching specs are omitted.
- Temperature rating f: REI Co-op Trailmade 20 Sleeping Bag 21 vs Sidewinder SL 20 Mummy Sleeping Bag 20
- Insulation type: REI Co-op Trailmade 20 Sleeping Bag synthetic vs Sidewinder SL 20 Mummy Sleeping Bag down
- Packed weight (lb): REI Co-op Trailmade 20 Sleeping Bag 3.29 vs Sidewinder SL 20 Mummy Sleeping Bag 2.25
- Packed size: REI Co-op Trailmade 20 Sleeping Bag 10 x 13 in vs Sidewinder SL 20 Mummy Sleeping Bag 6.5 x 8 in
- Product note: REI Co-op Trailmade 20 Sleeping Bag Replaced the discontinued Trailbreak 20; recycled synthetic insulation; ISO Lower Limit 21F, Comfort 31F vs Sidewinder SL 20 Mummy Sleeping Bag 650-fill DownTek hydrophobic down with body-mapped FireLine ECO synthetic at pressure points; designed for side sleepers; center ambidextrous zipper