External optical viewfinder, there are two focal length angles of view (28mm/35mm), four colors (black/red/blue/orange) options:28mm focal length angle of view (135 full frame), no frame.35mm focal length angle of view (135 full frame), no frame.Installation method: plug it into the camera's hot (cold) shoe, but it is not recommended to use models with too high SLR warships (the parallax will be large).Regarding the lens: The viewfinder lens is an optical resin lens, and some slight gray or fine scratches are inevitable, and it will not affect the use.The viewfinder is small in size, transparent and bright, and it is very coordinated to install on various rangefinder camerasSuitable: for Leica cameraInclude: Viewfinder*1