A Complete Sleep System Good Down To 0ºC for 700 grams!
This one's for all the weight weenies out there. We're talking about thru hikers, adventure racers, bike packers, kayakers, fast and light climbers or just even more standard trekkers and travellers looking to minimise the weight and space of their kit.
Rab UK have designed an award winning sleep system that combines a sleeping bag and sleeping mat that is super comfortable and can go down to 0ºC for a combined weight of 700 grams and a crazy small pack size too.
The sleep systems combines the Rab Mythic Ultra 120 Down Sleeping Bag and the Rab Ultrasphere 4.5 Sleeping Mat.
While there are a number of clever little design features that degrees the weight and bulk, a large part of the weight saving can be put down to the use of their TILT fabric, and the bottom of the sleeping bag not having down or multiple layers of fabric where the mat can be achieving the insulation.
What is TILT?
To use Rab's words, TILT is a "Heat reflective Thermo Ionic Lining Technology (TILT), designed to reflect heat back onto your body". Basically it acts like a space blanket which not only stops radiant heat from escaping but it actually reflects it bag to you. The great thing about the use of TILT as an insulation is that it doesn't add any weight to the sleeping bag or sleeping mat because the TILT fabric is used in replace of the normal lining fabric on these products. So really there is no downside to it. The TILT insulation is so effective that the Ultrasphere 4.5 sleeping mat achieves an R-Value of 4.5 just by its construction and the use of TILT - it doesn't need any other synthetic or down fill added. This means it has an incredibly small pack size.
Two Products Working as one System
As eluded to in the intro, the other major factor in reducing the weight of the Rab sleep system is that the sleeping bag and sleeping mat work together to insulate you all the way around the body and, importantly for the weight factor, they don't double up on jobs. Standard sleeping bags have down underneath the torso and they sort of need to as the manufacturers don't know what you're sleeping on and want to seal the air in all the way round you. However the down crushed under your torso is largely useless as compressed down doesn't insulate at all. The Mythic Ultra sleeping bag contains no down or double up of fabric under the torso. Instead it has sleeves for the mat to slide in. As the mat is providing sufficient insulation it serves to insulate you underneath, and as the two items connect together they won't separate when you roll over to expose cold spots. Instead you tend to turn inside the sleeping bag as opposed to the whole sleeping bag turning with you.
Sleep System Good Down To 0ºC For 700 Grams
Traditionally, even having a down sleeping bag good down to zero degrees for 700 degrees was a good thing (and still is mind you). But now that Rab have thought about these two products in unison, you can get the sleeping bag and mat for just that. Not only is the total weight impressive but particularly the pack size. Considering the mat doesn't need any fill insulation and the sleeping bag doesn't have any fill under the torso, the pack size is truely amazing. Suddenly for multi-way hikes you can easily start thinking about a 40L pack instead of the traditional 65L+, and that's without even thinking much about the rest of your kit.
If you're in the mood of saving weight and bulk on your outdoor adventures, then the Rab Mythic Ultra / Ultraspere 4.5 sleep system is certainly worth a look. It's the obvious choice for those real weight weenies like fast packers, adventure racers, bike packers and climbers, but it's even great for those traditional hikers just looking to lighten the load. Usually the investment into weight saving only yields a few grams at a time, but with this one fell swoop you can be looking at easily dropping a kilo.
