We additionally coat the material of our products on the inside and in the floor area with a PU coating. This is a protective layer of polyurethane. The PU in liquid form is a durable impregnating agent that is sprayed on as a thin film and has strong water-resistant properties. The layer can be applied easily and repeatedly (especially in the bottom area of backpacks) to the entire textile surface or to individual fibres. The PU coating also provides additional robustness, making textiles more tear-resistant and abrasion-proof.

In contrast to a conventional impregnation or a DWR, a PU coating gives the fabric a permanent impermeability. However, after a certain time the softeners dissolve and the PU coating becomes leaky. Here, however, we are talking about periods of time that even our products designed for durability will not "experience".

Per- and polyfluorinated chemicals, PFAS for short, are substances that are harmful to the environment and health and have been the preferred choice for impregnating textiles due to their previously almost unrivalled water-, dirt- and grease-resistant properties. Due to its widespread use, PFAS has left traces all over the world - in drinking water, breast milk, the air and reproduction. The harmful fluorocarbons also degrade very slowly or not at all. A time bomb for humans, animals and nature. In the meantime, there are environmentally friendly alternatives. With the DWR (Durable Water Repellancy) impregnation, we have completely dispensed with PFAS since 2019 and can still guarantee the high-performance water and dirt-resistant properties of all our products. The environmentally friendly surface treatment, which is harmless to health, takes us one step further on our path of responsible and sustainable action.

We also take care in the construction of our backpacks that little moisture can penetrate into the inside of the backpack through openings or other product features. For example, a drawstring under the lid compartment (snow skirt, spindrift collar) keeps the moisture out if the lid compartment of the backpack should ever slip.

A product that is designated as weatherproof can withstand wind, rain and sun. This is measured by the following standards:

The wind resistance of the fabric is measured using the wind flow measurement (CFM). It expresses how easily air (usually at a speed of 48 km/h) can flow through a fabric. The lower the rating number, the more wind-repellent the fabric. This means < 1 cfm repels the most wind and is therefore 100 % windproof. The more "hard-shelled" or dense the fabric, the less wind will normally penetrate it. 

To measure the rainproofness of a material, a water pressure test is used to see if water leaks through the material. Here, the force of wind-driven rain is the benchmark. It is 2 psi. Fabrics with at least 3 psi are therefore considered weatherproof.

 The UV protection factor or UPF indicates how many UV rays can penetrate a fabric. The lower the rating, the less UV resistant the product. A UV protection rating of 30 is typical for sun-resistant fabrics and blocks almost 97% of UV rays. 50+ offers the maximum protection. The tighter or heavier the fabric or the darker the colour, the better the protection.

That doesn't sound crazy at first. But if we look at the whole thing with a temporal component, then continuous weather influences can cause strong signs of wear on the material.

If this does not happen, i.e. if routine weather influences do not affect the material and it remains in a "like new" condition even after a long time, then we speak of weatherproof - and in terms of protection against moisture: waterproof.

The demands on the material of weather-resistant products are high. And ours is even higher. Because in addition to the essential characteristics such as robust, waterproof and durable, we are increasingly trying to use sustainable materials certified according to official environmental standards for our backpacks. In addition, we also try to offer the best possible weather protection for the seams, pocket openings and zips, as these are always weak points in terms of weather resistance. 

If water-repellent products are either made of fabrics that are so tightly woven per se that it is difficult for water to penetrate them, or if they are made of materials such as polyester or nylon that are more resistant to water due to their structure alone, or if they are specially treated with an additional coating or impregnation, the material becomes water-resistant. Water-resistant materials offer greater protection in wet conditions than waterproof ones. This means that water beads off the surface and cannot penetrate the material as easily. The technical term for this is "hydrophobic". However, in continuous or heavy rain as well as high pressure on the material, it cannot be ruled out that wetness will penetrate the inside at some point.

As a backpack manufacturer, we use tightly woven and thus waterproof fabrics for our products. In order to increase the water repellence of the material and thus make it water-resistant, we have exclusively used a DWR (Durable Water Repellency) impregnation since 2020. This means that we do not use PFAS at all and still ensure the high-performance water- and dirt-repellent properties of all our products. In addition, we provide the inside of the material with a durable PU coating.

Due to high water pressure (e.g. heavy rain) or additional high pressure on the material (e.g. bulging backpack), moisture can penetrate through the coating and the material into the interior. To prevent this, waterproof material is used for particularly extreme weather conditions.

Whether the material used can be defined as water-resistant or waterproof is decided on the basis of the definition used by the textile industry based on international standards for waterproofness. The hydrostatic water column is a unit of measurement that indicates the water pressure that the material can withstand before the water penetrates. For outdoor products, it is the load limit above which a textile becomes water-permeable. The pressure is given in millimetres. Thus, 1 bar corresponds to about 10,000 mm water column.

Generally speaking, the higher the value, the denser the material. But what do we really need? The European standard DIN EN 343:2010-05 (protective clothing against rain) defines a water entry pressure of 800 mm as the lowest limit. From here on, one speaks of waterproof. Everything below this is declared water-resistant.

Depending on the load, duration and intended use to which the material is exposed, higher values are certainly required. For example, a person weighing 80 kg exerts a pressure of 1,000 mm when lying down, 5,000 mm when sitting and 14,000 mm when kneeling. The material must withstand this pressure and prevent the water from penetrating over a longer period of time. A good guideline for the waterproofness of outdoor clothing is 10,000 mm.

However, a waterproof material does not necessarily mean that the product is waterproof. The entire construction, including potential water entry points such as closures, seams, pockets and openings, must be sealed or even welded waterproof and must be able to withstand stresses such as use and care (washing, drying or mechanical stresses) over the long term. Because the state of use of the product also has an influence on the waterproofness. Therefore, proper care and cleaning are really crucial for the performance of the product.