The output of HID bulbs diminishes gradually over time with use, but the human eye has difficulty discerning this reduced output.
Therefore, it is important that users have a way to measure the ongoing LUX from their lamp, in order to know when its output has declined to the point where replacement is recommended.
This light meter accurately displays light levels in terms of Lux (lx) and Foot Candles (fc) which are a measure of lighting intensity. Lux Meter includes handy carry-case.
(Model #LX1010B)