Sea to Summit Thermolite Reactor Extreme – Sleeping Bag Liner and more

Sea to Summit Thermolite Reactor extreme


If you want to have a camping with light equipment, you can save money on your sleeping bag first.

In combination with some additional clothing, which is always present, the comfort area of the sleeping bag can still be pressed a whole bit. At some point, we can conclude that have two possibilities:

  1. Buy new warmer but still a lightweight sleeping bag.
  2. Buy a warm sleeping bag liner.

Since 1st choice comes to warmer light sleeping bags with considerable costs, the 2nd choice seemed always worth a consideration.

Recently, I had been looking for a suitable sleeping bag liner of Sea To Summit, which here produces the Thermolite Reactor series a whole series of differently warm liners. As the winter is coming, I asked the Bergzeit company to make a Thermolite Reactor Extreme available for testing. A few days later I had the Thermolite Reactor Extreme, let’s check the warmest sleeping bag liner.

390 grams of the Thermolite fabric weighing 110Gr / m² is now at my home and waiting for their first use. According to the product, specifications are up to 14 degrees extra drain.

It is nice that my kitchen scale does not work or the liner is somewhat lighter ?


Weight of Thermolite Reactor extreme

Weight of Thermolite Reactor extreme

Of course, you can then pull off the pack again, which you leave on tour eh at home.


Weight Packsack Thermolite Reactor Extreme

Weight Packsack Thermolite Reactor Extreme


If you are looking for sleeping bag liners, you can also find the company Cocoon on the Internet, which produces only liners.


Here, a comparable product is given as 9 degrees.

If the Thermolite Reactor Extreme would bring 10 degrees, I could be with my 3-seasons sleeping bag and a bit of clothing prima in the moderate winter.

Light, cheap and a small pack make the Reactor an attractive product when it brings performance.

Since the night temperatures in my house are still not sufficiently cold, I have to give a real test review.

I used the Reactor only indoor so far, which I liked but quite well comfortable. Freedom of movement is ensured above all because the fabric is even stretchable. Full of anticipation for the performance of the liner I exchanged my blanket in the bed against the Reactor. This has unfortunately not worked completely. Pure emotionally, it was as if I had put 200 bucks in mine pocket. The weave is not tight enough to prevent the potentially warm air between the liner and the body from volatilizing through body movements. As a liner, under a sleeping bag or windproof Bivy might look different, which is still to be tested.


Fabric of Thermolite Reactor Extreme

Fabric of Thermolite Reactor Extreme


I have a sleeping bag from Deuter, the Neosphere -10, for women means the -5-degree comfort range (and I’m convinced of it …)

In the Chilean summer, he was on an expedition to the Andes in 2015. Highest camp at 5.500m at -20 / -25 degrees.

First, of course, a good camping pad brings a huge advantage. (Thermarest NeoAir XTherm).

For the sleeping bag I have a Termolite Reactor with heat output 8 degrees (so not the warmest, thought me the second warmest must be enough). Since I was really a frightened in the night to freeze, then still a light down jacket, a second light to the legs and my mittens over the feet (fit not quite, but for the toes is enough). To do this, a towel on the head, one on the neck, liner gloves for the fingers and the whole with long underwear I always eh. prepared for the night.

I must say I’ve never had such a restful and deep sleep like that up there! Some colleagues of mine have had their -25 degrees sleeping bags, but rather simple sleeping mats. They did not have frozen but also had no great sleep. I think I did everything right and saved a lot of weight … everything I had in my sleeping bag, I had to have eh.

Conclusion: If you do not want to afford two sleeping bags is with such a liner quite well!
Of course, I also use the liner for any huts – is my only hut sack.

Here again the facts before in the next weeks here still a praxistest follows

Length: 210cm

Width: above 90 cm, lower narrow (not measured) because mummy shape.

Weight: 399 grams Manufacturer’s data, 358 grams of re-weighed (15 grams of packsack)

Temperature gain: according to manufacturer up to 14 degrees, practice test follows

Material: 110g / m² Thermolite (100% Polyester)



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