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  • High-loft, premium 850-fill-power European goose down offers superb warmth with minimal weight; Ultra-Dry Down™ water-repellent treatment protects down from moisture
  • Ultra-Dry Down is a water-repellent polymer treatment applied to the down; Ultra-Dry Down retains 60% more loft and absorbs 30% less moisture than untreated down
  • With a European Norm (EN) lower-limit rating of 46°F, the Sea to Summit Spark SpI will help keep you warm on 3-season backpacking adventures in warm weather
  • You can also use the Spark Sp I as a booster bag by slipping it inside another sleeping bag to add warmth
  • Ultralight 10-denier Pertex® Quantum® fabric with a durable water repellent treatment sheds moisture
  • Soft 15-denier nylon fabric lines the sleeping bag for excellent comfort next to skin
  • Left-side 1/3-length zipper saves weight over a full-length zipper
  • Compresses to the size of a grapefruit


View all Sea to Summit Men's Sleeping Bags

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Best Use Mountaineering, Backpacking
EN Lower Limit 46 degrees Fahrenheit
EN Comfort 54 degrees Fahrenheit
Temperature Rating (F) 46 degrees Fahrenheit
Temperature Rating (C) 8 degrees Celsius
13.8 ounces
12.3 ounces
Ultralight Yes
Shell Ripstop nylon
Zipper Location Left
Insulation Type Down
Water-Resistant Down Yes
Fill 850-fill goose down
Fill Weight
7 ounces
6.3 ounces
Lining Nylon
Sleeping Bag Shape Mummy
Fits Up To (in.)
79 inches
72 inches
Shoulder Girth (in.)
60 inches
57 inches
Hip Girth (in.)
52 inches
50 inches
Stuff Sack Size 4 x 9 inches
Stuff Sack Volume 2.5 liters
Compressed Volume 1.55 liters
Gender Unisex
Rated 4 out of 5 by from Incredibly Small First a disclaimer, I have only tried this bag out indoors because I may need to exchange it. It is amazingly small and light. Taking the sleeping bag out of the stuff sack is like pulling a rabbit out of a hat. It's incredible how well it packs down. BUT... this may come at the cost of warmth. The bag is practically see-through. It is warm for how thin it is, but I may exchange it for the *Sea to Summit SPII*, which is also small, but 10 degrees warmer. Another note, I usually feel claustrophobic in mummy bags, so I was worried about the shape of this bag and 1/3 zipper, but it was actually extremely comfortable. It is shaped very well.
Date published: 2015-07-26
Rated 5 out of 5 by from My go-to sleeping bag! I've had this bag for over a year now, and this is definitely my go-to sleeping bag. Even when the temps drop past the 46 degree rating, I just add thermals and a down jacket. This bag weighs 14 ounces... that's just insane. You can't go wrong with this bag. I will agree the cut is tight, but helps keep in the warmth. I highly recommend you pick this bag up... you won't regret it.
Date published: 2015-05-30
Rated 4 out of 5 by from Constrained Quality The quality of this bag is great, and it's warm. I thought I'd try the mummy bag, but it was unfortunately too constraining at the feet. I also didn't notice that the zipper doesn't go all the way down. So I thought I could open it on warmer nights to get some more foot room, but that's not possible. For someone who doesn't mind the lack of room around the legs and feet, this would be a great bag. It's super light, and it's put together very well. But I'm going to try the Sea to Summit Trek for some extra leg room.
Date published: 2015-05-14
Rated 5 out of 5 by from Design changes? Received package very, very, very fast! Product appears to match specs. However, I was surprised to see that the product photo doesn't match the product in my hands. The logo is not on the silver side. Product contents tag is on the silver side. Zipper back side appears to be on the silver side. So overall it seems like the silver side is now the inside? And the orange side is now the outside? So confusing. If this is the case I think it actually looks better. The only thing that concerns me is the fabric on one side is more durable so I want to make sure I use the correct side. Overall very happy. I haven't tested it yet but everything appears to be well made as expected.
Date published: 2014-03-12
Rated 5 out of 5 by from Great Bag with a Great Weight I have only used this one night so far, but it was great. The temps were right around the 45 degree mark and I was actually a bit too warm. (I am a very hot sleeper and I was sleeping on a NeoAir X-Light). The size is amazing as it stuffs down to about 2/3 the size of a nalgene bottle. I am 5'11 and opted for the long bag. I think I would have been fine with the normal one.
Date published: 2016-03-23
Rated 2 out of 5 by from short side zip a real problem for a tall guy like me, the short zipper is problematic. I ended up exchanging this bag as a result, without ever using it. Everything else (weight, compressability, etc) seemed good, and if you don't mind shimmying into your bag from the top, this would likely work for you. Just not for me.
Date published: 2017-03-23
Rated 4 out of 5 by from Sea to summit We bought these for bike packing. They are very light weight and pack up very small. The only thing I would do to make it better would be another zipper or a longer zipper.
Date published: 2017-05-23
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Is the compression bag included?

Asked by: Irdie
Yes, the Spark SpI bag includes lightweight Ultra-Sil® compression sack and a storage sack.
Answered by: REIservice
Date published: 2017-05-30

How do you compress the sleeping bag?

Asked by: imis
The sleeping bag is easily compressed by using the plastic buckles and webbing that are part most compression sacks. Simply put the sleeping bag inside the compression sack and pull down on the webbing located on the side of the compression sack. You may find you need to do this process gradually one by one.
Answered by: REIservice
Date published: 2017-04-27

Would it be possible to provide the shoulder girth in inches for the Sea to Summit Spark SP 1?

Asked by: Leatherneck
The Spark SpI will have a shoulder girth of 57 inches for the regular and 60 inches for the long.
Answered by: REIservice
Date published: 2017-05-30

Is the 46 degree rating sufficient for a 2017 NOBO AT thru-hike starting in mid-April or am I better off getting the II with the lower temp rating? Obviously concerned about temps at the beginning and end of the trek.

Asked by: Adventure Hero
Based on the information provided, we recommend going with the Sea to Summit Spark Sp II Sleeping Bag.
Answered by: REIservice
Date published: 2016-09-12

Can two of these bags zip together? Since they're only 1/3 length zippers, I'm guessing they can't, but no harm in asking.

Asked by: Gangof5MA
No, two of these sleeping bags cannot zip together.
Answered by: REIservice
Date published: 2015-09-20
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