"Great for boaters and water enthusiasts who need to find their way home after dark, the Night Vision Monocular is lightweight, compact, waterproof and floatable. It works by collecting available light and focusing it in the image intensifier where a photo cathode converts energy into electrons. They then accelerate across an electrostatic field and strike a phosphor screen, emitting an image you can see. Built-in infrared illuminator for viewing in complete darkness. Hand strap, carrying case. Viewing range 5-675'. FOV(100 yds.) 70' Exit pupil 4.5mm. 7x2.3x3.1"". 15 oz. 3V lithium battery not included. Closeouts. Russia."