The Leica Viewfinder Magnifier M 1.25x magnifies the viewfinder image by one quarter and the Leica Viewfinder Magnifier M 1.4x by two fifths. They provide a major aide in framing the subject at focal lengths above 50 mm. The viewfinder 1.25x is recommended for focal lengths of 50 mm or more and the viewfinder 1.4x for focal lengths of 75 mm or more. By magnifying the rangefinder images, it greatly enhances focusing accuracy, especially when shooting at telephoto focal lengths. The 1.4 x viewfinder magnifier turns into magnification of 1x (0.95x with M8 Models); this combination allows comfortable viewing of the subject with both eyes. The viewfinders are simply screwed into the viewfinder ocular of the Leica M. A small chain attached to the Leica M's carrying strap eyelet prevents it from being lost or damaged. A leather pouch is supplied for safekeeping when it's not attached.