The Sig Sauer TANGO4 Rifle Scope features a versatile 4-X zoom range for adapting to mid to long-range tactical engagements, or for hunting multiple species of game in varying habitats. 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. A 30mm main tube provides maximum turret adjustment for elevation. The LockDown Zero System features a resettable zero, zero-stop, and auto-locks down at zero, so you can adjust the turets 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 coating resists abrasion on exterior lens surfaces. The TANGO4 Rifle Scope is IPX-7 waterproof rated for complete immersion up to 1 meter, and fog-proof. Versatile 4-X zoom range Well suited for hunting or tactical applications First focal plane optical system LockDown Zero System Illuminated reticle Motion Activated Illumination Low dispersion (LD) glass IPX-7 waterproof rated 30mm main tube