Latch replacement for storm window

Hello there. Looking at your storm window, I believe it was one manufactured by "Karey Castle". However, I don't believe these parts are still available. We do carry the 91-176 storm latch, but I don't think they will fit your storm window. 

My suggestion would be to take your storm window to a local hardware store or glass shop in your area to see if they repair storm windows. They may have some of these older parts laying around or something that might fit your storm window frame. I am very sorry for the inconvenience.