ACOG 4x32 Scopes with Red Dual Illumination & BAC-M16 / AR15. Features Dual Illumination (Fiber Optic provides daylight illumination and tritium illuminates reticle at night). The reticle ranges out to 800 meters for 5.56(.223 cal).ALWAYS ON, ALWAYS READY - Most ACOGA(R) models are battery free, featuring a tritium/fiber optic illuminated reticle that automatically adjusts the brightness based on available light.TAKE CONTROL - Several ACOG models are designed with a user adjustable brightness setting powered by a single AA battery. The 3.5x35 LED and 4x32 LED models both offer six adjustable brightness settings.RUGGED, RELIABLE HOUSING DESIGN - Fixed-power design allows for minimal moving parts to create a nearly indestructible sighting system.SHOCK-RESISTANT - Proven to withstand recoil from a .22LR to a .50BMG and everything in between. Easily passes U.S. Military drop test requirements.EXACT TARGET DISTANCES & HOLDS - Most ACOG models feature a bullet drop compensating and target-ranging reticle for decisive aiming."BOTH EYES OPEN" DESIGN - "Both eyes open" shooting using Trijicon's Bindon Aiming Concept(TM) (BAC) feature allows for improved situational awareness.