The SIG SAUER TANGO6T Rifle Scope features a versatile HDX 6x Super-Zoom Advanced Optical System, allowing you to adapt to CQB and mid-range tactical engagements in a snap. A first focal plane optical system allows you to compensate for bullet drop and wind drift through the scope's entire magnification range, by maintaining consistent size of the reticle in relation to the target (subtension) at all settings. The LockDown Zero System features a resettable zero, zero-stop, and auto-locks down at zero, so you can adjust the turrets for long range shooting, and then quickly return to your original zero after the shot. The illuminated reticle utilizes MOTAC (Motion Activated Illumination) to turn on when the weapon is moved, and turn off after a period of inactivity to save battery life. Low dispersion (LD) glass provides incredible clarity and brightness, and LensArmor and LenShield coatings resists abrasion on exterior lens surfaces. The TANGO6T Rifle Scope is IPX-8 waterproof and Argon gas-purged for fog proof performance. Versatile HDX 6x Super-Zoom Advanced Optical System LockDown Zero System Motion Activated Illumination Fast-focus eyepiece SpectraCoat, LensArmor, and LenShield lens coatings Stealth ID technology Low dispersion (LD) glass IPX-8 waterproof Fogproof