Each lighting device for vehicles must display mandatory approval markings to indicate compliance with ECE standards. These markings provide information about the approval and the country where it was obtained. The following markings are mandatory on the lens of each approved lighting device:

• ECE Approval Number:
• • This number begins with the letter "E" followed by a number indicating the country where the approval was carried out (e.g., E1 for Germany, E4 for the Netherlands).
• Approval Symbol and Number:
• • The ECE round symbol or the rectangular symbol with an approval number is displayed, usually with the designation "R" for lighting. This number is provided once the lamp has successfully passed the approval process.
• Standard Number of the Approved Lighting:
• • Depending on the type of lighting, the standard number is also required (e.g., R6 for indicators or R23 for reversing lights).
• Function Code:
• • There are codes to indicate the type of light function, such as:
  • • A for position light
    • B for low beam
    • C for high beam
    • R for reversing lamp
    • F for fog lamp
    • These codes are often combined with the standard number.
• Light Intensity Marking:
• • For headlights and some other lighting devices, a marking indicates that the light intensity meets ECE requirements. It may also specify whether the lamp is intended for vehicles driving on the left or right side of the road.
• Vertical and Horizontal Markings (sometimes required):
• • For some lighting devices, additional markings may be added to indicate the correct installation position, such as a "TOP" marking to show which side should face upwards.

These mandatory markings are essential for compliance with ECE regulations and aid in identification, approval verification, and installation. They must be clearly visible and legible on the lens or surface of the lighting device, often in the form of engraving or printing.