An ORIGINAL EARLY ISSUE Marbles arms tang sight (aka Peep Sight) for all calibers in the Winchester 1905, 1907, 1910. It DOES NOT comes with sight aperture. Tang screw Hole spacing on the base of the sight is 1.000 inches outside and 0.800 screw-center to screw-center. Sight adjustment is 1.680 inches to 2.015 inches, with an 18 degree angle. It is now Very Difficult to find an ORIGINAL W13 tang sight in this condition and especially with the W13 clearly stamped underneath the bottom.