EtaProof® is one of our favourite performance fabrics. It is the most breathable weatherproof fabric in the world, tried and tested extensively since decades. It outperforms conventional synthetic shell layers when it comes to durability, comfort and sustainability. It is an organic cotton weave, so densely woven that it becomes mechanically waterproof when the fibers expand from moisture.

Many of our core users are dedicated fans of this unique fabric, and use it for all weather conditions except heavy rain and wet snow where you will get wet eventually. Long before ”outdoor” was even the name of an industry, long-staple cotton was the mainstay protection for every cold weather expedition. The North Pole, The South Pole and Mt Everest have all seen the first flag being pitched by brave expeditioners dressed in cotton clothing.

We use two different weights; 205 g/m² is used for jackets and the heavier 240 g/m² is used for pants. EtaProof ® is GOTS* certified (Global Organic Textile Standard).

(Dyed cotton bleeds when worn and washed, particularly darker colours. Your EtaProof® product will therefore develop a beautiful patina after some time, similar to a pair of denim jeans.)

Products using EtaProof®


Bean-based polyamide
Traditionally, polyamide is extracted from petroleum which isn't the best solution for the environment. However, we have been able to replicate 60% of this process using castor bean oil. This lessens the dependence on fossil fuels and creates a more sustainable alternative to traditional polyamide.
Merino wool
More than one hundred years into the development of synthetic materials, wool keeps outperforming any other fabrics when it comes to moisture wicking, warmth and odour fighting capabilities. We use 100% Merino wool, known for its quality, softness and ability to regulate body temperature even during high-intensity activity.
Organic cotton
Klättermusen took the decision in 2006 to work only with organic cotton to lessen our environmental impact. Conventional cotton is considered one of the most polluting crops due to the heavy use of pesticides and insecticides in production, and there are also concerns regarding worker’s rights, child labour as well as unsustainable water consumption.
Certified down
RDS-certified means that the entire supply chain is audited, and the welfare of the birds is respected during their entire life cycle. For example, live-plucking and force-feeding of the animals is strictly forbidden and all the down is fully traceable back to the farm.
Recyclable fabrics
In theory, this is a great concept. In reality, there are very few options to recycle any clothing at all. Regardless of which material it is, there are few possibilities for ordinary people to recycle their clothes, and many of the outdoor companies claiming “closed loop systems” are simply collecting jackets and storing them in their warehouse, waiting for better days to come.
Recycled polyamide
Polyamide (also known as nylon) is a synthetic fibre made from petroleum, creating an extraordinarily strong and versatile fabric. At Klättermusen, 90% of the polyamide we use is recycled from post-industrial waste, and we were the first outdoor company to use recycled polyamide across our whole clothing and backpack line in 2009.
Recycled polyester
At Klättermusen, we have worked with recycled polyester for more than a decade. It makes sense from every perspective, most notably from a sustainability point of view.


Box construction
The down channels in Klättermusen products are made with our Box Construction, meaning that we keep the down evenly distributed with internal sidewalls instead of penetrating seams.
Duracoat™ is a unique surface treatment that Klättermusen has developed to improve durability in high-abrasion areas. It is a coating that is applied to particularly vulnerable places such as the shoulders or elbows, increasing wear resistance by up to five times.
The Global Organic Textile Standard (GOTS) is the worldwide leading textile processing standard for organic fibres. This includes ecological and social criteria backed up by independent certification of the entire textile supply chain.
Mass Flow Resistance
MFR means Mass Flow Resistance and is our index on measuring wind permeability and breathability. Over the past 30 years, 100% windproof outer shells have become the industry norm despite limitations in breathability and the clammy feel it produces for the wearer.
Water repellent
Durable Water Repellents, DWRs, is a treatment that repels water and creates a waterproof or water resistant surface – or hydrophobic surface to use the scientific term. On breathable/waterproof garments, the water repellent prevents the face fabric from becoming saturated with water and impeding breathability of the garment.
The bluesign® approval on our fabrics means that it complies with the highest standards of consumer safety by using materials and techniques that save resources and minimize environmental impact.


Cutan® is our waterproof/breathable technology, developed in our lab in Östersund and tried and tested extensively in the wilderness around our office in northern Sweden. We started to work with Cutan® 20 years ago when we took the decision to completely move to PTFE-free membranes to become fluorocarbon-free in production.
Any of our core users are dedicated fans of this unique fabric, and use it for all weather conditions except heavy rain and wet snow where you will get wet eventually.
Keprotec Kevlar from Schoeller® is one of the many ways we make our gear last longer, an extremely protective fabric originally developed for motorcycle racing.
Our multi-functional WindStretch™ is a softshell fabric with outstanding abrasion resistance and stretch. It will keep your body at the right temperature during high-intensity activity with its breathability and moisture-wicking properties. All WindStretch™ fabrics are bluesign® approved.
PrimaLoft® is a lightweight synthetic insulation with properties similar to down. It is highly compressible and packable to bring as an extra layering when in need of extra warmth. Compared to down, PrimaLoft® absorbs significantly less moisture, and maintains its insulating abilities even when wet.