Technically, all kinds of fabrics can be considered "waterproof" until water pressure begins to leak or cut it through. However, they are divided into "water-resistant", "waterproof" and "water-repellent". Data from the so-called "hydrostatic test" is used worldwide to determine the fabric's waterproofness. In an area of 1 cm², a special device creates a pressure equivalent to the pressure of a water column of a certain height, which is measured in millimetres. And finally, we get those 10'000 / 20'000 / 30'000 mm waterproof laminates.