The volume of each backpack is measured using a standardised method: we fill the main compartment as well as each pocket with little balls. Then we empty these balls into a graduated container, which gives the equivalent volume in litres.

We carry out laboratory tests to validate every component: fabric, buckles, straps, foam and zips. For example, for fabric: resistance to abrasion and tearing, colour-fastness in UV light, resistance to washing, waterproofing, etc. Then, a test that replicates several years of use of the backpack is conducted to check the strength of the assemblies. The backpack is filled with weights and placed on a mannequin that replicates thousands of fast walking movements.