We carry out laboratory tests to validate all component parts: fabric, buckles, straps, foam and zips. For example, for fabric: resistance to wear, tearing, colour-fastness under UV rays, washing, waterproofing. A final test on the finished product simulates the kind of treatment to which it will be subjected over several years, to assess the strength of the assembly: the backpack is weighted then placed on a dummy which then reproduces the movement of fast walking over thousands of cycles.