The Hyperion 32F/0C sleeping bag is among the lightest in its class while still providing high-performance during backcountry pursuits. The bag uses thermally-efficient box baffled construction in key areas to ensure warmth and comfort in an ultralight package. Designed with high-quality materials and Therm-a-Rest performance features, the Hyperion keeps your pack featherweight without sacrificing an ounce of performance.



During ultralight objectives, the 16-ounce Therm-a-Rest Hyperion TM 32F/0C Sleeping Bag provides peak performance for uncompromising adventurers. All Therm-a-Rest sleeping bags and quilts are also covered by our Better Sleep Guarantee. When you wake up on a Therm-a-Rest sleeping bag or quilt, they are confident you’ll wake up feeling better than ever. If you are not completely satisfied, return it within three months with the original receipt of purchase and they will give you a full refund- no questions asked. This is offered as they have the assurance of great materials engineered for performance and pack-ability.

The pack-ability is from the down fill, which is 900 fill Nikwax hydrophobic down, which stays drier and maintains loft (keeping you warm in damp conditions) 60 times longer than untreated down when exposed to water. Dries faster, absorbing 90 percent less water and dries 3 times faster than untreated down. This wonderful effect is created with a water-based (Zero Fluorocarbon [ PFC ] ) formula, which is seen to be safe for humans and the environment. Which can easily be re-applied, and fully re-treated, when washed with ‘Nikwax Down Wash Direct’. Additionally, this is a water-based formula which is safe for you and the environment. The sleeping bag is filled with hydrophobic down, what is even more reassuring is that the Down fill used has been ‘Responsible Down Standard Certified’, meaning the down used, was obtained from an animal which was treated humanely. Safeguarding the welfare of the geese that provide down and feathers for the Therm-a-rest down products. We at SLOAN! feel this is such an important factor when selecting your down-filled items.

The sleeping bag can easily integrate with your mattress using the included ‘Synergy Link’ Connectors. These removable straps join the two items together and keep the Hyperion Sleeping bag on your air mattress or sleeping pad while allowing you to move freely under your quilt. Integrating the two, to minimize cold spots and keep you comfy through the night. This reduces heat loss, maximizes efficiency and utilizes the warmth of your insulated mattress. Which could help you sleep better when your sleeping bag and mattress work together. For optimal comfort and efficiency sleeping. Increasing the sleeping bags versatility further, by optimal efficiency and comfort, removable for versatility.

The very interesting ‘Gear Up and Give Back’ scheme, which aims to support The Conservation Alliance for the conservation of wild spaces, where Therm-a-Rest has partnered with Cairn and Gear Fix, to offer a way you can provide older gear, including sleeping bags, and quilts. If you send in your older bag, the repair team will make any necessary repairs, and restore the item to a resellable standard. The proceeds of the sale of the item, go directly to the conservation alliance projects. Now what is even more impressive, is Therm-a-rest is provided with a 40 percent discount on a new item. A very smart win, win, win.


Fast and Light Sleeping Bag

The Hyperion sleeping bag is designed for Comfort range 5 C, a Transition Range 0 C, and a Risk Range -15 C. This sleeping bag can be used during any fast adventures almost down to 0 C.


The patent-pending, easy-to-use SynergyLink TM connectors ensure that you stay on your pad, so you can stay warm all night. To insert your mattress, start with a fully inflated pad. Insert the head of the pad into the fabric connector near the head of the sleeping bag, then bend the pad and insert the foot of the pad into the other connector. This joins your sleeping bag with your mattress for optimal comfort and efficiency sleeping out under the stars.

Therm-a-Rest® sleeping bags are designed to accommodate a wide range of sleep positions. Therm-a-Rest sleeping bags are designed with extra room in the torso to allow your shoulders, elbows and hips to move freely. At the head and foot, the fit is closer, keeping you warm and decreasing overall weight. Also, the placement of our SynergyLink connectors is optimized to keep the mattress secure while you roll, yet allow the head and foot of the bag to rotate 90-degrees in either direction, following you for maximum comfort and warmth.


Our Testing Experience


The box baffled construction, with zoned insulation, maximizes warmth and saves weight by intentionally placing fill where you need it most.

The superiority of downs warmth to weight ratio is unmatched, and 900 fill (Fill power is the cubic inches an ounce of down can fill in a lab container, gauging the loft or fluffiness of the down) goose down is as high as most can achieve. This is a great standard to be held to.

Classically the higher the fill power the warmer the sleeping bag. However, naturally, this means that often less down is used when it is more efficiently functioning.

The sleeping bag was very warm at temperatures of 10 C, needing the reviewer to unzip the bag and leave the highest distribution areas of down off them to stay cool. At 5 C the bag kept the reviewer comfortably warm when zipped up, and sleeping well.

Below this, and heading down to around 2 C the bag begins to show its limits, a lesser aspect if you are a wiggler when you sleep. The issue is that the bag is tight around the lower limbs and feet, and the down fill is preferentially placed at the top section of the sleeping bag (zoned insulation), this is a great idea, and really does keep you warm. Until you turn or twist in your sleep. The whole bag twists with you, so the lesser filled underneath of the sleeping bag becomes one side of your bag, and vents out all the trapped in warmth. Meaning at cooler temperatures, you wake in the night with a cooled bottom and an experience of cold. This is reduced again, by moving back on to your back, and ensuring the bag is back into the original position.



The Hyperion sleeping bag is the lightest in class. With unrivalled pack-ability: lightweight materials and precise design, pack down into the included minimalist compression sack.

The compression sack and storage sack are included. The ultra-light package of the compression sack and the sleeping bag, are a very impressive weight, most sleeping bags could only dream to be at light as. The high-quality materials and the smart design, combined with the 900 fill count down, means that you can reduce the amount of down required to achieve a comfortable warmth. So the weight of the sleeping bag can be kept far lower. Forming a true ultra-light sleeping bag. This is seen with this amazingly light sleeping bag. One of the lightest on the market. Great for gram shaving, fast and light activities, and for those who enjoy a lighter backpack.

Our long weighed in at 510g. Yes, that’s right, half a kilo! Totally ‘featherweight’ (pardon the pun) without sacrificing an ounce of performance.




Classically the shape of the sleeping bag correlates with the desired use, and camping adventure planned. The Hyperion is described as a ‘comfort fit’, ‘ergonomic shape and longer zipper providing a more human-friendly fit than other ultralight sleeping bags’.

Ultimately it is a very slimmed down ‘mummy’ shaped sleeping bag, which means it is shaped like a sarcophagus and is a snug fit, that tapers towards the feet. This allows it to remain a warmer option, lighter and packing down more effectively.

The downside is this shape is often more restrictive for the user, and this can affect comfort. Our experience with this sleeping bag was that the sleeping bag ran a little too tight, and is not as long as preferred. The perceived length may have been due to the inherent desire to wiggle up the sleeping bag to assure foot and ankle comfort. There is no room for tossing and turning as you can experience with the wonderful quilt options, provided by therm-a-rest.

It is hard to move while in the sleeping bag, there is not enough space for the movement of a hip, to flex a leg or move at the knee or hip. Your legs need to both move together, and cannot move that much. There is also a lot of pressure on the outer ankles and feet.

There can sometimes be a slight loss of heat of the legs. Perhaps this is due to it being a little too tight in the legs, means pressure on the bag occurs, meaning some loss of warmth. Altering comfort, and generating cooler spots.

The tighter leg area, actually made it hard for the reviewers at times to sleep on their sides. You cannot turn in the sleeping bag, and often the reviewer opted to not use the synergy links, to ensure the bag could move more. The comfort would likely increase, with a wider foot box and more space for the legs to move. This would perhaps increase the weight a little, however, this would be a worthy increase for such an improvement.

Our reviewers were tall, and at 6.2, chose the long, the hood sits snugly. Likely from the need to move up the bag, to avoid the tighter foot box area. This is also seen as a benefit for warmth, as there is no ‘dead space’ to warm. This is one reason the bag is nice and warm. The second is the amazing fluffy down fill, which feels so nice and soft, like pressure down on a cloud of warmth.


Packed Size:

The sleeping bag packs down to one of the smallest packed sizes the reviewer had had the pleasure to have a review of. Down is super compactable, it is almost more compactable than you would ever expect. The high-performance backcountry pursuits and fast travel bush adventures.

The bag can be stored in the provided storage bag, which is a nice feeling and perfect size, for a small storage space.

The compression sack is incredibly lightweight and able to compress the bag down to a smaller size than any other down sleeping bag reviewed by the reviewer at this time.

This is also due to the sleeping bags ultra-thin, light, compressible material and the high-quality high fill goose down, which means less down is required for the same temperature regulation. It compresses to something only a little larger than the average lightweight down jacket! For a whole-body covering sleeping bag, this is very impressive.



The very stylish black forest colouring is a perfect look, and the sleeping bag looks slick.

It is ultralight, and one of the lightest pieces in its class. The Hyperion sets a new standard for high-performance outdoor equipment. Light packing and constantly adapting high-end materials.

There has been a very recent change to the design, where they removed the ThermaCapture TM lining, which was lined to trap radiant body heat and retain warmth without adding bulk or weight. We were a little unclear if the bag we had, was one of the bags with the Therma Capture lining, or the newer redesigned version without. We assume that it was the newer version without the Therma Capture material.

The left side zipper is the half-length of the bag, meaning you do sometimes generate a little bit of a wiggle, to enter and exit the sleeping bag. This is made a little harder when the synergy links are being utilised. Additionally, the zipper only has one slide, so you can not regulate temperature while the bag is still zipped up.

This design also meant that the bag could not be fully opened and used as a quilt or blanket, or warmth shared. Furthermore, a second bag could not be connected. This was a shame when travelling with another.

The reviewers were lucky enough to not experience a zipper misalignment or similar problems, perhaps the zipper design is effective at preventing this occurring. However, the reviewers wondered, if they did get something like that occurring out on the trails, how they would be able to fix this?.


Weather Resistance:

Down has a new shield of protection against the weather. For too long the issue with down was that water and moisture, negatively affected the warmth, and comfort a down sleeping bag provided. Now with the Hydrophobic down, the whole sleeping bag, is in a way a water repellent bag. All the fabrics are designed to repel moisture and together increase the weather resistance provided.

The new 10 D nylon ripstop technical fabric, with a DWR on the outer shell fabric, prevented any form of water collecting into the bag during the review.

Managing to also shake off all sand and grit that was literally pilled over it. This all left the reviewer feeling mighty protected against the elements.


Application and Uses:

For objectives that demand a light pack and a good warm night’s sleep, the Hyperion provides peak performance for uncompromising adventurers. A good option for ultralight travel and fast and light ultralight adventures. Summertime and transition temperature lightweight travel.

The zipper has a minimalist button, for closure at the top of the zipper, effectively preventing the zipper from unzipping during your mobile sleep.

900-fill Nikwax Hydrophobic Down: Stays drier and maintains loft 60 times longer than untreated down. When exposed to water. Dries faster, absorbs 90 percent less water and dries 3 times faster tab untreated down. Additionally, the Nix wax performance lasts, maintaining performance for 5 washes, and is fully retreated when washed with Nikwax R Down Wash Direct R.

SynergyLink Connectors: Integrate the bag with a mattress for optimal efficiency and comfort; removable for versatility. Two sets of loop attachments, for the use of the single provided strap. This removable strap allows you to decide the most suitable location for the synergy link, for your needs. Securing your bag to your pad. For a more secure feel. Easily remove the bag and the Synergy Link connectors, and have a more free sleep.


Features and Benefits

  • Comes in three size options Small, Regular, and Long.
  • Ultralight:One of the lightest pieces in its class, the Hyperion sets a new standard for high-performance outdoor equipment.
  • 900 Fill Goose Nikwax Hydrophobic Down:Stays drier and maintains loft 60 times longer than untreated down. When exposed to water.
  • Synergylink Connectors: Integrating the sleeping bag with a mattress for optimal efficiency and comfort; removable for versatility.
  • Box Baffled Construction uses mesh walls to maximize loft and minimize cold spots in key areas.
  • Unrivalled Packability:Lightweight materials and precise design allow for a smaller packed size than ever before
  • Comfort-Fit:Ergonomic shape and longer zipper provide a more human-friendly fit than other ultralight bags
  • Responsible Down Standard Certified:Certification that ensures that the waterfowl in the down supply chain are treated humanely.
  • Zoned Insulation:Maximizes warmth and saves weight by intentionally placing fill where you need it most, 70% on the top and sides with 30% on the back
  • Heat-trapping draft collar
  • Zipper draft tube
  • Snag-free zipper
  • Cinchable hood
  • Insulted foot box
  • Compression sack and storage sack included
  • Limit 0 C ( Comfort Range 5 C and Risk Range -15 C )
  • 454 g (regular size), 510g (Long).
  • You can get a long if you are taller and/or wider!

The Hyperion is crazy lightweight, packing down as small as any 0 C bag our reviewer had tested. Reliable and versatile warmth for your ultralight camping.

Therm-a-Rest Hyperion™ 32F/0C Sleeping Bag RRP £355 (regular size) more information can be found at

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