Illuminated Reticle
A battery-lit reticle whose aiming reference glows, aiding aim in low light or against dark and visually busy backgrounds.
An illuminated reticle uses a small battery and an internal light source to make all or part of the aiming reference glow, usually in red or green. The purpose is contrast: against a shadowed animal, a dark tree line, or in failing light, a plain black reticle can disappear into the background, while a lit one stands out clearly. Most designs offer several brightness levels so the shooter can match the glow to conditions without washing out the field of view.
On a first focal plane scope the entire reticle grows and shrinks with magnification, so illuminating only the center portion keeps the bright point usable at every power. The feature adds nothing in good daylight, where the etched glass reads fine on its own, but in the first and last light of the day it can be the difference between a confident hold and a guess.