Abstract: A binocular mountable on a headgear, includes two optical systems, one for each eye of the user. Each system includes at least an objective lens and an eyelens. The binocular is pivotably attached to the headgear. When the headgear is in position on the user's head, the objective lenses and the eye lenses can be quickly swiveled out of the way to facilitate free and unaided vision, and returned to the position of binocular-aided vision. The binocular optical systems can be configured to provide either telescopic or microscopic effects. Moreover, the mounts of the lenses are transparent and integrally formed with the respective lenses. Thus, a continuity of visual field without "tunnel" vision is achieved. Hook and loop type fasteners can be used to attach the optical systems to the headgear, which can be either a cap or a visor. Additionally, a laser light/sun light shield can be provided. The optical systems can define bifocal optical systems. A single optical system (i.e.