Modern vehicle accessories of different types now frequently carry an "E" approval mark valid throughout Europe. This "E" mark, which is made up of a combination of letters and numbers, is clearly displayed on the product and shows the application tested, the country in which testing was carried out and, where appropriate, the vehicle type to which approval applies. EC type approval for exhaust systems, for example, are always issued for a specific vehicle type, whereas in the case of lighting, they apply to an entire group of vehicles, e.g. motorcycles.
This certification mark is the sole proof of legality stipulated by law, i.e. no written report or entry in the vehicle documents by TÜV (German Technical Inspection Association) is required. However, when it comes to installing accessories, the relevant guidelines of the Road Traffic Licensing Regulations (StvZO) must always be observed.
At at a roadside check or a TÜV vehicle inspection, the registered keeper is only required to show the "E" mark. It is then up to the official in charge whether to check the mark with the Federal Motor Transport Authority (KBA) in Flensburg (or equivalent type approval authority in other countries), which is able to decode all certification marks.
Original parts on newer vehicles that have been given an "E" mark at the factory may only be replaced with accessories that have likewise undergone E-approval. An E-certified mirror may not, for example, by replaced with a mirror that only has TÜV approval under the German vehicle licensing regulations.