Zacuto C100 Z-Finder Pro Optical Viewfinder for Canon C100 LCD, 40 mm Lens Diameter, 1.8x Magnification Snaps onto the camera's LCD screen via a mounting frame 40mm diameter optical lens magnifies the LCD by 1.8x A diopter enables specific tuning to match your eyesight Three Extender Frames allow extended tuning One anti-fog cover is installed and one is included