Looks like one I pulled off a cheapy ***** airgun to mount a laser. Still have it in the shooting box with all the other sights and screws I've pulled off the various guns. My best guess. One of the better-made airguns, it actually had a rail machined into it, all the others just had the rear sight screwed on BB-gun style. All of $25, IIRC. Was supposedly an AK trainer. If it's an airgun sight, it'll fit an 11mm rail rather than our 3/8" .22 rails.