How to use it 1.Close your right eye and sight an object with your left eye, rotating the center focus wheel until the image is sharp and clear. 2.Open your right eye and close your left eye. Rotating the right eyepiece until the object sighted is sharp and clear. 3.Both sides(eyes) are now in focus and you will need to use only the center focus wheel to focus on the other objects. Specification Objective lens diameter: 25mm Eyepiece diameter: 12mm Field of view: 374ft/1000yds Objective lens coating: FMC broadband Angle of field: 7.5° Type of Prism: BAK4 Magnification: 10x Exit pupil distance: 20mm Focus system: Center & Right eye