Kelty Cosmic 20 Down Mummy Sleeping Bag
- 20 F rating, ISO comfort 32 F, limit 21 F
- 550 fill power RDS down
- About 2 lb 6 oz (regular), stuffs to 13 x 7 inches
- Fits sleepers up to 6 ft (regular)
- Recycled shell and liner, PFAS-free DWR
- Limited lifetime warranty, stuff sack included
Last refreshed Sep 8, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A light, packable down mummy bag for three season backpacking with traceable down and recycled fabrics. Down loses warmth when wet, and the comfort rating is warmer than the bag's name.
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ASIN: B0CSPKCJZKModel: Cosmic 20 DownCategory: Sleeping Bags
Colors Available
Sizes Available
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Overview
Backpackers and campers who want a packable down bag get a three season mummy with traceable down and recycled fabrics. Trapezoidal baffles hold the down in place, and a draft tube backs the zipper.
Low weight and small packed size suit backpacking from spring to fall. The comfort rating is warmer than the headline number, so cold sleepers should plan a liner or warmer layers.
Who it's for
Three season backpackers and campers up to six feet suit the regular size. Winter campers or very cold sleepers need a warmer bag.
Pros and cons
- Light and packable
- Traceable RDS down
- Recycled, PFAS-free fabrics
- Dual direction zippers
- Comfort rating warmer than headline
- Down weakens when wet
- Weight listed two ways
Performance notes
Down traps warm air in its loft, and baffles prevent it shifting to the sides. The DWR finish sheds light moisture, but soaked down loses insulation. The comfort figure is the more reliable guide for warm sleeping.
Specifications
| Brand | Kelty |
|---|---|
| Model | Cosmic 20 Down |
| Dimensions & fit | |
| Maximum Height Recommendation | 72 inches |
| Item weight | About 2 lb 6 oz (regular) |
| Item Dimensions L x W | 78 x 30 inches |
| Stuff size | 13 x 7 inches |
| Capacity & performance | |
| Temperature Rating | 20 F; ISO comfort 32 F, limit 21 F, extreme -11 F |
| Construction & materials | |
| Fill Material Type | 550 fill power down, RDS |
| ShellMaterial | Recycled 20D nylon taffeta |
| Material | 50D polyester lining, PFAS-free DWR |
| Included components | |
| Included Components | Sleeping bag, stuff sack |
| Warranty & support | |
| Warranty Description | Kelty limited lifetime warranty |
| Other details | |
| Shape | Mummy |
| Closure Type | Half-length dual direction zipper with draft tube |
Frequently asked questions
How do I pack the Kelty Cosmic 20?
It compresses into the included stuff sack to about 13 x 7 inches.
How warm is the Kelty Cosmic 20?
It is rated to 20 F, with an ISO comfort rating of 32 F, ISO limit of 21 F and ISO extreme of -11 F.
What height fits the regular Kelty Cosmic 20?
The regular fits sleepers up to 6 feet. Short fits up to 5 feet 6 and Long up to 6 feet 6.
Is the Kelty Cosmic 20 down ethically sourced?
Yes. It is 100% RDS certified and traceable through the product tag.