This Mossberg manufactured intermediate variation S102 sporting rear sight is designed for the later model 42B bolt action rimfire rifle which has one threaded and one non threaded (rear most) hole in the barrel for mounting this sight. This sight has the elevation (wheel) screw with notches and the front mounting screw without the knurled windage lock nut. The overall condition is good exhibiting a mixture of original blue finish with a brown patina and some scattered specks of rust. The early variation mounting screw is included and does not have provision for the knurled windage locking nut. (file photo)