The climb is steep. Your body produces heat and moisture. At the same time, clouds gather and the first raindrops begin to fall.
Now your hardshell has to perform two seemingly opposing tasks: reliably keep rain out and transport the water vapor produced as quickly as possible to the outside.
That’s exactly where our new R’Tech Nano membrane comes in. It combines high levels of weather protection with exceptional breathability and is completely free of PFAS and PFC.
The technical principle behind it is complex. Its name is deliberately simple: Swiss Cheese Membrane Technology.
What does a membrane actually do?
A membrane is a very thin functional layer within a hardshell’s fabric construction. It is barely visible from the outside, but it is essential to how the jacket works.
Its job is to control water, wind, and moisture precisely:
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Raindrops should not get in from the outside.
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Wind should not pass through the material.
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Water vapor should be able to escape from the body to the outside.
That sounds simple. Technically, however, it’s a major challenge.
If a membrane is especially dense, moisture can build up inside. If it is highly permeable, weather protection can suffer. That’s why hardshell technology long meant one thing above all: a compromise between waterproofness and breathability.
With R’Tech Nano, we aim to significantly reduce this compromise.
How Swiss Cheese Membrane Technology works
The R’Tech Nano membrane is made from polyurethane, or PU for short. It is hydrophobic, microporous, and completely free of PFAS and PFC.
Microporous means that the membrane has a very large number of ultra-fine pores. These openings are designed to let water vapor escape to the outside while preventing raindrops from passing through the membrane.
To make this principle easy to understand, we use a typically Swiss comparison of sizes:
If a single membrane pore were as large as a hole in Swiss cheese, a raindrop would be about the size of a stadium. Water vapor, by contrast, would be as fine as a hair.
The comparison is deliberately visual, but true to scale. It shows why the membrane works differently in each direction:
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Fine water vapor escapes to the outside.
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Large water droplets stay out.
The result is a hardshell that protects you from precipitation while helping transport moisture away during physical activity.
23,577 grams of water vapor per square meter
How breathable a membrane is measured under controlled conditions. The value shows how much water vapor can pass through one square meter of material in 24 hours.
The R1 Alpine Tech Jacket with R’Tech Nano achieves a water vapor permeability of:
23,577 g/m²/24 h
A leading jacket on the market reached the following value under the same test conditions:
15,893 g/m²/24 h
In the direct comparative test, the R1 Alpine Tech Jacket’s breathability was around 48% higher.
What does this mean for you?
During a strenuous climb, your body heats up. You start to sweat, and water vapor builds up inside the jacket. If it can’t escape sufficiently, your clothing feels damp from the inside, even if no rain has gotten in.
The high water vapor permeability of the R’Tech Nano membrane helps transport this moisture outwards more quickly.
41-meter hydrostatic head for reliable protection
A material’s water resistance is measured using what’s known as hydrostatic head. It describes the water pressure a material can withstand before moisture penetrates it.
The R1 Alpine Tech Jacket with R’Tech Nano achieves a hydrostatic head of:
41 meters, or 41,000 millimeters
Under the same conditions, the tested comparison jacket reached 35 meters. In the comparative test, the R’Tech Nano construction therefore had a water resistance six meters, or around 16%, higher.
Especially important: The higher water resistance was confirmed even after three wash cycles.
A high hydrostatic head provides extra protection when the material is exposed not only to rain but also to mechanical pressure. This can happen, for example, when:
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a backpack’s shoulder straps rest on the jacket
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you sit on a wet surface
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wind drives rain against the material
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the fabric is put under strain while climbing or on a high-altitude tour
Why lab values don’t tell the whole story
Technical measurements make materials comparable. However, they can’t fully capture how a garment feels to wear on a tour.
How dry and comfortable you feel also depends on several factors:
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Intensity of your activity
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Temperature and humidity
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Jacket fit
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Base and mid layers used
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Ventilation options
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Personal perception of warmth and sweat
Even the best membrane can only work if moisture is transported through the clothing layers underneath and out to the outer layer.
That’s why a cotton shirt under a highly breathable hard shell is still a poor combination. Cotton retains moisture and dries slowly.
Hydrophobic from the ground up
The R’Tech Nano membrane is inherently hydrophobic. This means the material repels water and barely swells.
As a result, the membrane itself needs no additional coatings or pore sealing. The laminate stays smoother, reducing the orange-peel texture seen with some membranes.
It’s important to distinguish between the membrane and the outer fabric: even with a hydrophobic membrane, the face fabric needs a water-repellent finish. At RADYS, this treatment is PFAS- and PFC-free.
The water-repellent treatment makes water bead on the surface. The membrane underneath provides the actual waterproof protection.
Completely PFAS- and PFC-free
Many conventional microporous membranes are based on PTFE or related fluorinated technologies.
PFAS are often called forever chemicals because many of these substances barely break down in the environment. They can remain in water, soil, and living organisms for long periods.
In 2014, RADYS became the first apparel brand in the world to switch its entire collection to PFC-free water repellency. With the new R’Tech Nano technology, we’re taking another step: the membrane itself is also completely free of PFAS and PFC.
This shows that high-performance weather protection, high breathability, and more responsible use of materials don’t have to be mutually exclusive.
“Our R’Tech Nano membrane shows that high-performance weather protection and a PFAS-free membrane are not mutually exclusive.”
Adrian Ruhstaller, founder of RADYS
R’Tech Nano in the Modular Layering System
Within the RADYS Modular Layering System, the R1 Alpine Tech Jacket is the outermost protective layer.
You can combine them in different ways depending on your trip and the temperature:
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R5 Base Layer to wick moisture away from the skin
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R4 Mid Layer for extra warmth
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R3 Insulation Layer in cold conditions
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R1 Alpine Tech Jacket for protection from wind, rain, and snow
The goal isn’t to wear as many layers as possible. Each layer should have a clearly defined function and work together with the others.
This allows the R’Tech Nano membrane to deliver its best performance.
Made for demanding moments in the mountains
RADYS develops its outdoor sportswear in Switzerland for people who need to rely on their gear in changing conditions.
R’Tech Nano is the next step on this journey: a high-performance membrane technology that combines strong protection, high breathability, and more responsible use of materials.
Or, put more simply:
Sweat escapes. Rain stays out.
More protection. More breathability. More sustainability.
