Radiation



Advanced Combat Optical Gunsights (ACOG) are a series of telescopic sights manufactured by Trijicon®. The ACOG was originally designed to be used on the M16 rifle and M4 carbine, but Trijicon® has also developed ACOG accessories for other firearms. Models provide fixed power magnification levels from 1.5× to 6×.  ACOG reticles are illuminated at night by an internal phosphor illumination provided by the radioactive decay of Hydrogen-3, or Tritium.  The Tritium illumination has a usable life of 10–15 years. Some versions have an additional daytime reticle illumination via a passive external fiber optic light pipe.