Reference number (headlights)
The reference number indicates the brightness of a high beam headlight in cd/4300 (rounded). It is often listed as an additional indication on the ECE test mark.
Common indications are: 10 / 12.5 / 17.5 / 20 / 25 / 27.5 / 30 / 37.5.
In Germany, a maximum of 4 headlights switched on at the same time is permitted. The sum of the reference numbers must not exceed 100.