Night Owl Lightweight Night Vision Monocular (4x) 4x Zoom Field Of View: 56 Ft @ 200 Ft 500x Ambient Light Amplification 32-ft Dia. & 150-ft Powerful Ir Illumination Marine night vision monocular with lightweight, water-resistant housing High-grade, all-glass, camera-quality objective lens with 4x magnification 56-foot field of view at 200 feet; powerful infrared illuminator for moonless nights Exclusive steel stringer system for added precision; requires 3-volt lithium battery