UKC

Considering its barely credible weight, the warmth on offer from this combo of sleeping bag and mat is nothing short of outstanding, says John McKenna. It's a big investment, but one that mountaineers, backpackers and bikepackers may consider game-changing.

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Thanks for this John - it looks like a really interesting concept. I had a tryout of one of those bags in George Fisher, and I was surprised how roomy it was. I  wasn't able to try combining it with the mat though.

I hope this encourages more manufacturers to come up with symbiotic pairings like this.

In many ways they have https://www.ukclimbing.com/gear/camping/sleeping_bags/therm-a-rest_hyperion... I think I did that review in 2019. I'm not trying to say Rab is copying or anything, just that they have come up with a very similar solution to Thermarest by following logic - minimizing sleeping bag weight by accepting that for many any insulation below the sleeper is redundant, so do away with it. I still regularly use the bag and mat from my review as they are still by some way the lightest sleeping set up I have. 

Good stuff, Toby. The Hyperion 32 is my current bag for the same reason. I only pair it with a Thermarest mat in winter, though (an Xtherm NXT). In the warmer months I lie on a Klymit X-Frame, which is probably out of design intent but seems to work (the lower down squidges into gaps in the mat, making it surprisingly insulated)

I've just sent Dan some copy on super-mega-ludicro-ultralighting that may be interest.

Straps under the mat?  Tried that on my homemade quilt 8 years ago.  Doesn't work.  You spend all night lying still, trying not to let the cold air in.  IMHO, you need a sheet of fabric to close the underside, to prevent draughts.  Adds 100g but makes the quilt 10 times better.

Probably less than 100g with modern lightweight fabrics, Dave.

Regarding if any manufacturer is copying others, the concept has been active since at least the mid 80s. I think the first one I saw was a sample from Rab.

Hi Dave,

I'm not sure what you mean, this bag isn't a quilt and there is a thin uninsulated fabric underside to close you into the bag as you can see in one of the photos at the start. This I imagine adds less than 100g to the weight of the bag. It works well for me, but as I mention it'll depend on the sleeper.

I've used straps on a lot of different bags over the years and I like them, for this bag it's primarily good for orientating the bag upwards to ensure insulation is positioned correctly. On many other bags though I like this just to ensure I stay on the mat more and stops me rolling off as well as keeping zoned mapping positioned well. 

Are you pretending to be young and not remembering the Macpac Neve, which had no down on the bottom, just a sleeve to slide a Thermarest into? That was over a decade ago and doubt it was the first, either.

I have an ME Xero MM that must be over ten years old that had two fabric sheets on the underside, sewn to fit balloons to eliminate the need for the ballooned fabric. Manufacturers have been doing this for years.

I have since unpicked the tubes thinking that I could fit a thermarest uberlite 3/3 I picked up cheap but, though it does fit (just), it pulls the top fabric so tight with me in it it compresses all the down over the top. I intended to add a dart of fabric in at some point but with the sudden and dramatic decline of MMs I haven't needed it. Considering dusting off the MM kit for a return to the Saunders next year so I might have to get the sewing machine out.....

do these combined systems mean you have to put your bivi bag around the mat as well as the sleeping bag? or can you keep the mat under everything?

Now you mention it the name rings a bell, but to be honest I didn't remember it. Partly I guess that over the last twenty years or so, Macpac has been particularly prominent in the UK market. I did review one of their tents perhaps 6 or 7 years back here on UKC but they seemed a bit half in half out of the UK (and perhaps European) market. 

Did ME make it especially to double as a balloon bed or did some one modify it for you? Don't remember hearing about them.

BTW, to anyone in general, I'm not trying to claim Thermarest did this first! I suppose lying on something warm then pulling a cover over you rather than getting into a bag goes back to the stone age.

Yep, especially for balloons! I had drunk the balloonbed kool aid already by that point so when I saw one in the ME factory sale, I was all in! It was a warmer combo than the balloonbed/PHD Minim 300 combo it replaced.

Weighs about 450g, has approx 170g of down and is the EXL construction so pretty figure hugging/no dead spots.

https://outdoorsmh.blogspot.com/2013/03/first-look-mountain-equipment-xero-...

It’s a shame Macpac have pulled back from the UK market. Not just for their tents, sacks and sleeping bags but also their clothing. Maybe it’s not as good now but a lot of the clothing they were selling here in the mid-2000s was really good, I’m still using most of the stuff I bought nearly 20 years ago.

You can do either, it's up to you. I would prefer with this to keep the bag around everything so I can use the straps on the mat though. I feel like you would be warmer overall.

I still have one of those, got damaged in a stove accident. I brought it for a trip to the Arctic when I was 18, so that's 29 years ago!

You'll need a bigger bivi bag then so as not to compress the down and lose warmth...

Aren't most bivi bags big enough to cope with the mat being inside? Suppose it depends on the size of the mat, sleeping bag and person, but I've not had a problem with it.

No, many are not.

Fair enough, I've not had a problem with it and I'm not aware of any of my friends having the problem either, but maybe we actually all have the same bivi bags

I remember a few bags from the early 90s with a sleeve for a Thermarest instead of fill. Definitely not a new concept.

Yeah, I had one of those. It was like being strapped to an ironing board - good idea in principle but it never worked for me!

My rab survival zone wouldn't fit the mat at all.

My alpkit bivi bag is notionally big enough for both, but not without compressing the down on the sleeping bag which defeats the object of having sleeping bag somewhat.

I can get a 3/4 thermarest in mine and it works- it’s the toe bit that struggles with a full length Matt.

Army surplus bag for the win - massive inside!

I remember drooling over the MacPac Neve in either the Cotswold catalogue or the Field and Trek one way back when!

You'd think as teenage boys we would have found other magazines to drool over, but very sadly, I know exactly what you mean!  

Rab actually already created a top bag like this, that you could combine with a mat in 2008... it was called the Quantum Top Bag AR. Which itself was just a redesign of their older Quantum Top bag, which just didn't have the fabric to hold the mat, and that has been around since 2001 if I recall correctly. I still use that one, and just put my mat inside the bag. My old balloon mat if I want to go really light. Big Agnes and others also had similar top bag designs that had a sleeve for a mat around 2008.