GPO USA 6-24x50 Passion 4X Riflescope (MOA Ballistic Reticle) - Manual (Page 32)

Illumination
Select PASSION™ 4X riflescopes come with an iCONTROL™ reticle
illumination system. The reticle illumination is a fiber optic feature
of your riflescope. The illumination dot helps you aim at game,
helps you see the reticle in extremely low light situations, and
assists in exact shot placement on targets that are very dark (e.g.
black bear).
The illumination can be adjusted simply, and set to whatever
brightness the shooter prefers, daylight or dusk. To adjust the
illumination intensity, simply rotate the illumination regulator.
The iCONTROL™ illumination system has an electronic power
management built in. This system will automatically turn off the
illumination dot after 3 hours of no regulator adjustments. This
“auto off” function will dramatically save battery life. In addition,
the electronic system has a capacity indicator. When the battery
reaches 15 % remaining battery capacity left, the illumination
point will blink 3 times when switching on the illumination dot.
This is an indicator that your battery is running low and needs
replacement. After the 3-blink indicator, the illumination dot
functions normally.