Courtesy of our native company Mola Mola, I got for testing the most technologically advanced undersuit model that the company currently offers.

According to the manufacturer's declaration, this model is dedicated to diving in waters from 4 degrees C. Where could there be a better test site than the caves located in the northern regions of Norway, on the border of the Arctic Circle? It was there that I decided to check the possibilities of the Thermoflexx + undersuit.

Places: Plura Cave

water temperature 4.8 degrees

and the Litjaga cave

water temp. 5.7 degrees

Test conditions: in combination with a heating vest, the version without heating and my favorite - a failure of the zipper in the drysuit, i.e. the undersuit flooded.

First impression.

The undersuit has a modern design and is made of two layers of materials (more on the manufacturer's website). The outer material is slippery, which makes it easier to put on a dry suit. The inner layer is fleece, nice for the body. If someone wanted to use it without thermo-active underwear (you can, it removes moisture / sweat from the body). Two-way zipper, which is a standard for diving undersuits, one chest closed pocket and two hip pockets, useful during breaks between dives. Convenient and hassle-free access.

Thermoflexx + undersuit, in contrast to the version without a plus, has additional layers of insulation in places most sensitive to thermal conditions, i.e. back / kidneys, chest and thighs. Sleeves end with standard thin rubber bands that we put on the thumb when putting on a dry suit and which is to facilitate the even distribution of the undersuit material on the forearms (no rolling effect). The elastics can also be placed under the collar of the dry suit, as an open channel between the suit and the dry glove (air circulation).

The endings of the legs are an interesting solution. Flexible thin material, also equipped with wide elastic bands and, interestingly, significantly wider and looser than the rest of the leg. At first glance, it looks like it's too wide. What was the idea of ​​the manufacturer? Most of the diving undersuits have narrow legs, often with such flexible material, but still tight around the ends of the legs.

When putting on thick socks under the undersuit, it is not a big problem, but it is worse with undressing and taking off the legs crimped on the socks or socks from under the undersuit. Meanwhile, in the Mola Mola undersuit, this end of the leg is wide and flexible enough that you can easily unroll it and take the sock off quickly. A big plus, an interesting solution that speeds up disassembly, which is especially important as it is warm on the surface.

And what immediately catches our eyes? The undersuit is equipped with four "holes" located around the abdomen / abdomen, two on the left and two on the right.

Frequent problems and questions that arise with divers - How to pass the p'valva hose and / or the power cable of the heating vest through the undersuit? You can leave the zipper unattached from the bottom or make your own holes in the material of the undersuit. This is a solution, but then we lose the continuity of thermal insulation. Air heated by our body has an escape route through these openings, towards the outside.

The second issue is the failure of the dry suit and the risk of flooding. In this case, it is easier and faster for water to get close to our body. A small detail, but it can be important for dives in very cold and demanding waters.

The company Mola Mola solved it very well. A trim made of a rubber-like artificial material is inserted into the holes in the material, something like moving "petals" that bend back and forth. When inserting or removing a hose / cable, they bend easily, creating a fairly tight structure. If not used, they shall maintain the integrity of the thermal insulation. The manufacturer has used holes on both sides of the undersuit, depending on which side the cable or hose is led out from. The lower openings for the hose from the p'valva, the higher ones for the power cord of the heating vest. Very nice solution, tested and it works.

Thermal properties.

Thermoflexx + undersuit, to the touch and when putting it on, is more "fleshy" than the thick fleece liners (Polartec) that I have used before. In this case, it translates into its insulating qualities. It is definitely warmer, comparable to very thick undersuits made of Thinsulate, but at the same time, thanks to the materials used, we get great flexibility and freedom of movement. The latter, very important for technical or cave divers, especially those who prefer two-cylinder twinsets (the ability to reach the valves). During flooding, the undersuit actually loses relatively little of its insulation capabilities. In my case, I was wet from belly to toes and still managed to survive 50 minutes. in water with a temperature of 5 degrees Celsius, which is my life record;) The "fleshy" material absorbed a large part of the water, which caused it to drain away from the body and allowed to maintain a lot of thermal properties. At this point, there is the only disadvantage that I noticed with this undersuit. The effect of "absorbing" part of the water translates into a longer return time, i.e. the drying process. In a very warm room it will take several or several hours, which is longer than for standard thick fleece liners.

Something for something, I choose thermals during flooding :)

Compared to several brands of undersuits made of thick fleece, this one will need about 1, maybe 2 kg more ballast, but less than the classic "eagle owls" made of Thinsulate material. The undersuit can be washed traditionally in a washing machine, at low temperatures and it does not affect its potential loss of thermal properties.


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