Trijicon ACOG 4×32 Scope with Chevron BAC Flattop Reticle TA31F includes Trijicon TA51 Flat Top Adapter. The chevron reticle of the Trijicon Gun Sight is designed to be zeroed using the tip at 100 meters. The width of the chevron at the base is 5.53 MOA which is 19? at 300 meters. This allows range estimation for silhouette targets. Trijicon TA31F ACOG 4×32 Scope with Chevron BAC Flattop Reticle features Dual Illumination (Fiber Optic provides daylight illumination and tritium illuminates reticle at night). The ranging reticle is calibrated for 5.56mm (.223 cal) flattop rifles out to 800 meters. Trijicon TA-31F 4 x 32mm ACOG Advanced Combat Optical Gunsights hit fast in any light. Trijicon ACOG 4 x 32 Riflescopes are internally-adjustable, compact telescopic sights with tritium illuminated reticle patterns for use in low light or at night. Bind on Aiming Concept (BAC) models feature bright daytime reticles using fiber optics which collect ambient light. Trijicon 4×32 ACOGs combine traditional, precise distance marksmanship with close-in aiming speed. Although Trijicon ACOG 4 x 32 Rifle Scopes TA31-F has 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.