These windows (in certain dimensions) may be built into high-rises subject to the regulations of the building code, i.e. up to an elevation of 100m (where there can be enormous wind pressures), which means they conform to special operational demands group C. That which a 20-employee window-making business cannot achieve, is once more guaranteed by central brand manufacturing by UNILUX: this window impermeability is tested out in control samples in the UNILUX test rig every week!