Night Owl Optics NOXM50 Monocular * Big light gathering lens * Sleek body style * Image intensifier tube technology * 500x Ambient light amplification * Easy one-hand operation * Powerful infrared illumination * 39 feet at a distance of 100 feet field of view * Infrared field of illumination of 35 feet diameter at 100 feet * Requires one CR-123/3 volt lithium battery (not included)