Abstract: A fastening system is provided with a wall ring as fastening device, a ventilator and a holding means, wherein the fastening device is provided in radial direction around the ventilator and the ventilator is connected to the fastening device via the holding means. The fastening device encompasses a first fastening geometry. The fastening system comprises the fastening device and additionally encompasses a holding device, wherein the fastening device encompasses at least one further, second fastening geometry for fastening the holding device to the fastening device. The fastening device and thus the wall ring axial ventilator can be fastened in a common manner to a unit via the first fastening geometry. The second fastening geometry serves to fasten the holding device to the fastening device, so that the wall ring axial ventilator can be fastened to a different design of a unit than a lamella heat exchanger.