With the ability to head out camping still sadly not allowed, Nick B gets out in the garden with one of Therm-a-Rest’s awesome new bags to our range for a great close-up look.

So, what is all the fuss about when it comes to the HYPERION?

Well, it is part of Thermarest’s new Fast and Light range and while I am not sure how Fast it is, I certainly am sure it’s light!

How do they achieve this? A combination of extremely high quality 900 fill power Goose down and an ultra-lite 10 denier outer shell fabric are the main ingredients. Adding zoned box wall baffle construction and focusing 70% of the down fill onto the top of the bag where it doesn’t get compressed are the others. The Hyperion comes in two temperature ratings, 20F/ -6 degree and 32F/0 degree, which both use the same high-quality 900-fill-power down to make them extremely warm whilst keeping weight to a minimum. Compressibility is also excellent which makes them a good choice for backpacking, wild camping, and even something as extreme as multi-day trail running events. However, you don’t get anything for nothing, and the payback for them being so light comes in 2 forms. Some obvious features have had to be removed like a full-length zip and internal draught baffles around the neck and they have a narrow cut which may feel restrictive to some. The taper in the knee and lower leg is particularly pronounced.

So, let’s get on to the stats. Below is a comparison table that shows all of the useful weights and measures of the bags.

As you can see from the stats, the Hyperion 32F/0 degree is very light for a mummy bag. Under 500 grams for the regular size. If you look around at the competition, the Hyperion generally comes out 100+ grams lighter than its rivals. That’s a pretty big weight saving and crazy light for a bag that will keep you warm close to zero degrees.

The exceptional quality of the down used in the Hyperion makes it stand out from the competition. The 900 fill power white goose down that has been responsibly sourced and treated with Nikwax hydrophobic down proofer is a winner. The treatment adds no weight but will help the sleeping bag maintain its loft and resist moisture from condensation in a bivvi bag or tent for many days longer than untreated down, a must when you are on multi day hikes or walking in rainy or humid conditions.

The 10 denier rip stop nylon is exceptionally thin, but in my opinion robust enough to stand the test of time. 8 or 9 years ago I bought a Mountain Hardwear ghost whisperer down jacket and at the time it was the first product to my knowledge that used a shell fabric this thin. You can literally see through it. Well, it is still going strong having seen a lot of wear, more than you would ever expect a sleeping bag to get unless you are a fan of bivvying out in rocky areas without so much as a sleeping mat for company.

A few small holes in high-wear areas otherwise still going strong

One thing to note is that even though the outer of the shell is treated with DWR , it will still absorb a bit of moisture due to it being so thin.

So, what’s the pack size like?

Well, take a look at the picture below. Not quite as small as a 1 litre Nalgene bottle but still really impressive. It easily fits across the bottom of a 22-litre daysack meaning for those weekend away missions you really can easily use a small and light pack if you want as it takes up very little space.

How about the fit?

Well you can see from the pics that it is a snug shape. One plus to this is that once you are in there is very little extra air space to warm up, so you get warm quick, and stay warm. The official measurements are difficult to really make much of but it’s safe to say that if you are any bigger than me you might struggle with the tapered shape.

I am 5’10 and the regular is plenty long enough. With a 45-inch chest measurement, there is less room than I would like, however, I can actually lie flat on my back with my arms by my sides and it is OK. I don’t have a problem with the taper around the hips and legs at all, but I don’t wriggle around much and also sleep on my back mostly. If you are a side sleeper it may be more restrictive but I don’t mind the feel of it. The toe box shape is really good, perfectly angled for your feet to naturally drop down and rest comfortably in the baffles. The hood is plenty big enough to fit a small pillow in there, like the sea to summit Aeros.

One upside to the narrower dimensions is that when you are pairing it with one of the lightweight mats from Thermarest like the Uberlite in the pics, it does fit perfectly and the shape stops you from “spreading out “off the sides of the mat. With the option of using the removable “synergy link” connectors it can also help you to stay on the mat overnight, however, unless the ground is pancake flat, I would say they are just a bit too flimsy to do a really good job but they do help.

What’s the feature set like?

Well, as mentioned earlier, you are basically buying this bag because of its lack of features and hence the light weight. No full-length zip means you can’t open it up and lay it out flat like a quilt in warmer temperatures.The omission of internal neck baffles means that when you are reaching the limit of the warmth of the bag some warmed air can be lost when moving around if you are a fan of sleeping with a hat on rather than the hood around your head like I mostly do. It does have a drawcord for the hood and a poppered tab which you can pass through the zip puller to stop it from opening up in the night. The hood also has a baffle around it so when the draw cord is done up a bit it does really pull in around your face.

Summary

Well, I quite like it, in fact I would definitely swap it for the ultralite summer bag I presently use (a RAB top bag) as it has a decent hood and some down on the bottom which the RAB does not have, making it a nicer bag for spring as well as summer. I particularly like the feel of the material on the inside, it feels great, really soft. My only real criticism would be the Zip, which is snaggy due to the very light weight zip guard, and small gauge zip that they have used, this is fiddly. Overall, I would add it to my gear cupboard tomorrow.

Take a closer look at the Hyperion HERE

This was written by Nick B, one of the Taunton Leisure buyers and outdoor experts. He spends most of his spare time climbing and running in the UK and Europe. His favourite day out would involve abseiling into a sea cliff followed by camping and an evening around the camp fire with his climbing partners.

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