The reticle of the Trijicon TA31 ACOG 4×32 Tactical Scope ranges out to 800 Meters for 5.56(.223 cal) and hit fast in any light. Trijicon ACOG 4 x 32 Riflescopesare internally-adjustable, compact telescopic sights with tritium illuminated reticle patterns for use in low light or at night. The Bindon Aiming Concept (BAC) scope features bright daytime reticles using fiber optics which collect ambient light. Trijicon 4×32 ACOGs Fiber Optics & Tritium Illumination Scope combine traditional, precise distance marksmanship with close-in aiming speed. Although Trijicon ACOG 4 x 32 Scopes w/ Donut Reticle have many features which are very advantageous for military use, they were developed by Trijicon without government funding. Designed for use with the M16 family, every feature of its mechanical and optical design was chosen for a single purpose: to provide increased hit potential in all lighting conditions – without failure-prone batteries.