Number of lamps included in delivery.
The headlight lamps (see “Purpose”) are paired and can be supplied either
one or
two at a time - the latter is ideal if you need to install or replace both lamps at once. Also, paired configurations can be found in models for auxiliary lighting, and sometimes such lamps are supplied in
sets of 10 or even 100 pieces - this can be useful, for example, for installing side lights on a bus or truck. But the dashboard lamps are sold exclusively one at a time.
The maximum continuous lamp operation time. This indicator is quite approximate and the probability that the lamp will work during this period is approximately 1 in 3. This is due to the measurement technique: a control batch of lamps is used until 63.2% of them fail, the resulting time and indicated as "maximum service life". However, the Tc data compared to the B3 guaranteed life (see above) provides a good estimate of the overall lamp life and its ability to last beyond the guaranteed life.
