Homologation: Only local adjustments prescribe the size of this sign. If the car has a Czech registration and license plate, it is governed by the Vienna Conventions of 1960, but with regard to the exceptions of the transit countries. So the car must be equipped according to local laws, in addition oversized needs need different permits. In the Czech Republic, the designation of an oversized cost is required for signs of 40x30cm, but 50x50cm is according to Italian, Spanish, Portuguese regulations. For example, with a caravan in Italy, there is no problem. When operating a truck it is good to find the appropriate legal regulations, we recommend consulting with the Czech Academy of the Czech Republic.