The NVD Binocular/Monocular Night Vision Device with Gain Control (BMNVDG) is a new concept that combines all the best features of a monocular and binocular into one fully functional night vision product. This modular system allows the user to switch from two Monoculars to a dual-tube Binocular with a simple press and slide of components. These modular pieces help eliminate the added weight of duplicate components, while remaining fully collimated and nitrogen purged.