Integrated Universal Mounting System for drilled and tapped shotgun receivers; Durable 6061 aluminum enclosed housing protects against debris and moisture; Large Viewing Window for fast target acquisition and large field of view; Aspherical Lens for distortion-free sight picture and truer colors; Motion Activation with 10 minute auto-shutoff; Top Buttons for quick adjustments; Parallax Free; Unlimited Eye Relief for rapid target acquisition; Side Load Battery for easy battery changes without having to rezero your optic; Waterproof / Fogproof / Shockproof