A sighting system as mission adaptable as you are. The Bushnell AR Optics 1-4x 24mm BTR-1 riflescope offers an illuminated, ballistically calibrated reticle, optimized for use with 5.56 rounds. BDC provides accurate ranging and aiming to 600 meters. Make lightning quick power changes with the Throw Down PCL lever. Caliber-specific reticle delivers every round with peerless accuracy. The fully multi-coated optics for incredible brightness, and fast focus eyepiece deliver maximum accuracy and reliability. Nitrogen purged to remove any vestige of internal moisture, and O-ring sealed to prevent the entry of dust or moisture. Made of high-durability aluminum alloy, anodize-finished and sealed to protect the inside from elements. Riflescope is rustproof, virtually scratchproof and a beautiful complement to even the most expensive AR platform firearm.