Directional indicator lamps and side repeaters are covered by ECE Regulation 6. This applies whether an individual lamp, part of a headlamp or multi-functional lamp (such as rear cluster light).
There are several categories of approval: Categories 1, 1a and 1b for front indicators; Categories 2a and 2b for rear indicators and Categories 5 and 6 for side repeater lamps.
Each category must be tested and certified that it emits a certain level of light, to a certain colour and produces enough output over a certain vertical and horizontal plane to guarantee a minimum amount of visibility once fitted. The amount of light output requires varies from 0.6cd (candela) for side repeaters to up to 400cd for Category 1b indicators.
For items that indicate conformance to ECE Regulation 6, there are different markings for each category of approval as per one of the examples below (see Model A for side repeaters and Model C for individual lamps).
Please note that aggregated ‘E’ marks may be displayed in tabular format with either multiple categories of this regulation, or alongside other regulations (see Model B).