An ORIGINAL Winchester Rear Sight No 22K. This was called the Later Rocky Mountain Flat top that had a wide base and short tip. The height of the flat top is 0.33 inches and it has a middle elevation insert with a single adjusting screw. The sight was used on later 1873, 1892, 94 and 70, 71 rifles; This was produced through 1952 when it went obsolete. The elevator (Part st22 or st40 or st23 depending on the rifle age) is correct for this sight.