A
(2)
| B
(8)
| C
(10)
| D
(3)
| E
(16)
| F
(6)
| G
(5)
| H
(5)
| I
(4)
| K
(2)
| L
(4)
| M
(8)
| N
(2)
| O
(1)
| P
(9)
| R
(9)
| S
(7)
| T
(5)
| U
(1)
| W
(7)
Useful life (of a lamp)
Hours of operation of a light source during which the chromatic characteristics of the light emitted are maintained.