High beams must be installed on the vehicle in pairs, either two or four. High beams require ECE approval, meaning they must have a small "E" marking on the headlamp. If a high beam has this marking, it is approved for road use and does not require registration or inspection at the TÜV (technical inspection association). An exception is made for lamps with a double "E" marking, which count as two headlamps in one housing and can, therefore, be centrally mounted and used as a single high beam. Headlamps without an "E" marking are solely work lights and may only be used off-road with a separate switch.