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Therm-a-Rest
Hyperion Sleeping Bag: 20F Down

4.216216216216216 out of 5 stars
37 Reviews
$549.95 - $579.95
Color:Deep Pacific

Size:

Quantity


Why We Like The Therm-a-Rest Hyperion Sleeping Bag: 20F Down

The Therm-a-Rest Hyperion Sleeping Bag: 20F Down delivers the same cozy warmth we've experienced in our beds at home, except this thing is lightweight like a feather for our slumbers out in the mountains. The box-baffled construction ensures evenly dispersed insulation and no cold spots, while the hydrophobic down retains warmth regardless of light moisture.

Details

  • Lightweight and packable bag built to keep you on the move
  • 900-fill Nikwax Hydrophobic Down maintains loft when moist
  • Zoned insulation organizes down to minimize weight, maximize warmth
  • SynergyLink connectors hold your pad in place while you roll over
  • Item #CAS00EO
Material
10D nylon ripstop (DWR coating)
Insulation
900-fill Nikwax Hydrophobic Down
Shape
mummy
Max User Height
[small] 5ft 6in, [regular] 6ft, [long] 6ft 6in
Shoulder Circumference
[small] 55in, [regular] 57in, [long] 58in
Hip Circumference
[small] 48.5in, [regular] 49.5in, [long] 51in
Foot Circumference
[small] 40in, [regular] 43in, [long] 46in
Bag Length
[small] 73in, [regular] 80in, [long] 85in
Draft Tube
yes
Pockets
none
Pad Retainer
SynergyLink Connectors (removable)
Fill Weight
[small] 11.5oz, [regular] 12.5oz, [long] 14oz
Degree
20F
European Norm/ISO Comfort Rating
32F
European Norm/ISO Lower Limit Rating
20F
Storage Sack
yes
Stuff Sack
yes
Stuff Size
6 x 8in
Claimed Weight
[small] 1lb 3oz [regular] 1lb 4oz [long] 1lb 6oz
Manufacturer Warranty
lifetime

Overall Rating

4 based on 37 ratings

Review Summary

1 Stars - 1 reviews
2 Stars - 1 reviews
3 Stars - 5 reviews
4 Stars - 12 reviews
5 Stars - 18 reviews

Fits Slightly Small

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?

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5 out of 5 stars

October 3, 2023

A Great Quilt Alternative

I use this on overnight hiking trips and sheep hunting. I compare it to my Enlightened Revelation Quilt. Both are great ultralight sleep systems that have concessions. Bag is a bit snug fitting, but it's enough space to be comfortable. The snug fit means there is no dead air inside the bag with you. Great storage options, super light, packs very small (I'd say x1.5 my 1L Nalgene). Very well built, material is soft. Order came quickly and price was fair. Good job on this bag Thermarest.

Conner L.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

4 out of 5 stars

August 28, 2023

Light for degree rating.

The 3/4 zipper takes getting used to. Warmer weather makes it tough. It is a narrower fit but is right for my body. Lightest bag in this class.

Kevin C.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

July 10, 2023

A number of years ago

A number of years ago I purchased a Hyperion 0 deg bag to replace a worn out old favorite. The Hyperion quickly turned into my new go to bag. Warm, very light, and quite roomy. It also became a favorite of my wife's for bike packing. This year I decided to get the Hyperion 20 for warmer trips. Only drawback is securing it from my wife who currently has it on a pack raft trip! Cascade Designs truly nailed it with Hyperion line up!

Ron C.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

June 27, 2023

Great bag

Have spent just a few nights in the bag. So far I love it. Packs down small and is crazy light. I haven’t had the chance to test the lower temp limit yet so time will tell. Only negative is the zipper not being full length, but this was a known feature and a compromise I was willing to make. Looking forward to many comfortable nights.

alex m.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

3 out of 5 stars

March 27, 2023

Extremely light- poor quality

I received the Hyperion 20 a few weeks ago and headed out to the backcountry short after. After the first night I noticed a tear on the outside of the bag. The temperature dropped to 20, however, though combining with a NeoAir XTherm on top of a RidgeRest I couldn’t get a good night sleep. Thermarest did great in creating an extremely light sleeping bad. Sadly it does not hold up to the standards I’ve set based on years of experience with high performance gear from them. Hope I can continue to purchase with confidence also in the future.

Kristofer
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

December 17, 2022

Ultralight furnace.

This bag is fantastic. It’s incredibly light, and warm. Its only downside is that the fit is snug but that’s to be expected in a bag that’s as warm and as light as this one. I used it on several backpacking hunts this season and it’s packed size is minuscule so I’ve got more room to pack out game

Jacob O.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

4 out of 5 stars

December 7, 2022

Great Sleeping Bag

Familiarity:
I've used it once or twice and have initial impressions
Size Bought:
Regular
Height:
5' 9"
Weight:
170

It's lightweight and packable. I haven't had a chance to get a full profile on the bag yet, but haven't had any problems with it. A seriously light sleeping bag that kept me warm.

Andrew L
4 out of 5 stars

October 5, 2022

Performs well

Great bag, packs down well, is very efficient without being too snug even for someone with wide shoulders. One thing I would change is the length of the zipper I would like a full length zip instead of the 3/4.

Ceasar G.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

September 19, 2022

Alaskan Adventure Bag

Just got back from using this sleeping bag on an Alaskan fly-in hunt for sheep and black bear near Delta Junction. After 10 days of usage, I would rate the bag an overall of 5 stars. Things most people don’t consider… this bag is rated for 32F comfort (ideal use temps), 20F limit (lowest you want to use it) and -9F risk (you might get severely injured). The hunt was low 30s to high 20s at night and the bag never had me more than slightly chilled, wearing only merino wool base layers. I would agree that this bags comfort limit is about 32F. Another reviewer gave this bag a very low rating as it wasn’t warm enough, then went on to say they wore several layers of clothes in the bag. This is not ideal. In a sleeping bag, especially compact ones like this, it’s a best practice to only wear your base layers and nothing more. When you start layering up, you won’t allow the down to insulate your body and trap heat, making you colder. I actually tested this, one night wearing three layers and found it very cold. Next nigh, only base layers, and was much warmer.

Jeffrey M.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site

5 out of 5 stars

August 14, 2022

Great lightweight bag!!

The material feels amazing and it is a perfect fit for my 5'1" frame.

Dyan M.
a Cascade Designs brand site

Originally reviewed on a Cascade Designs brand site