Kelty Cosmic Down Sleeping Bag 40F
- 40 degree rating, warm-weather summer bag
- 550 down fill
- 20D recycled nylon face, 50D recycled polyester lining
- PFC-DWR treatment on the fabric
- 3 seasons, one person, zipper closure
- 1.8 lb weight
Last refreshed Sep 28, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A lightweight, compact down bag for summer and mild three-season nights. The listing gives no length, width or height guidance, so confirm fit before you buy.
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ASIN: B0DT2FNYRMModel: Cosmic 40 DownCategory: Sleeping Bags
Overview
Down fill provides the loft in this Kelty summer bag, wrapped in a recycled nylon face and a recycled polyester lining. A PFC-DWR treatment is applied to the fabric.
Packable, light down warmth for warm nights is the reason to consider it. The limitation is a low rating that suits summer rather than shoulder-season camping, plus missing size dimensions.
Who it's for
Warm-weather hikers and campers who want something light and compact will find the weight and rating suit them. Cold sleepers, and buyers who need exact length and width, should look at other models.
Pros and cons
- Down fill for warmth
- Recycled face and lining fabrics
- Lifetime limited warranty
- Length and width not listed
- Fill weight not listed
Performance notes
Loft from the down fill traps air, which governs warmth for the weight. The face fabric and lining are thin, which helps compressibility, and the DWR finish adds some resistance to moisture.
Specifications
| Brand | Kelty |
|---|---|
| Model | Cosmic 40 Down |
| Dimensions & fit | |
| Size | Standard / Regular |
| Item weight | 1.8 poundslower than 75% of 33 sleeping bags |
| Capacity & performance | |
| Temperature Rating | 40 degrees |
| Construction & materials | |
| Fill Material Type | Down (550) |
| ShellMaterial | 20D recycled nylon |
| Fabric Type | 50D recycled polyester |
| Color | Dill / Duffel Bag / Cherry Mahogany |
| Warranty & support | |
| Warranty Description | Lifetime Limited Warranty |
| Other details | |
| Occupancy | 1 Person |
| Closure Type | Zipper |
| Seasons | 3 Seasons, Summer |
Closest rivals on specs
Helikon-Tex Swagman Roll Basic- Item weight 1.8 vs 2.1 pounds (-14%)
Frequently asked questions
What size is the Kelty Cosmic 40 Down?
It is listed as Regular or Standard size. The listing gives no length, width or maximum height, so check with the seller if you are tall.
Is the Kelty Cosmic 40 a winter bag?
No. The title calls it a warm-weather summer bag with a 40 degree rating, and the specs list 3 seasons, summer.
Is the Kelty Cosmic 40 filled with synthetic?
No. The fill is 550 down.
Does the Kelty Cosmic 40 have a water-repellent finish?
Yes. The shell fabric lists a PFC-DWR treatment.