E-mark is European type approval for vehicle lighting, shown as an E in a circle with a country number. It covers what the lamp may do on a road: the beam, the colour and the function. A forward-facing lamp without it is not road legal in E-mark markets, and in many of them it is not importable either.

CISPR 25 is an electromagnetic compatibility standard, not a lighting one. It governs the radio noise a component puts onto the vehicle's wiring and into the air. Class 4 is a demanding level, and it matters because an unfiltered LED driver interferes with the vehicle bus and with radio reception — a fault that reaches you through the distributor rather than the fitter.

FMVSS 108 is the United States federal standard for vehicle lighting. It is separate from E-mark and satisfying one does not satisfy the other, so a product sold into both markets needs both sets of documents.

For an importer the practical point is that all three are documents, and the document has to name the model you actually bought. A certificate for a sibling model in the same series is the most common reason a shipment is queried, and it is avoidable at the order stage.