New screw on rear sight notch for older Crosman 760 Pumpmaster air rifles, as well as the Crosman 2100 and 766. This is part 8 in the 2100 diagram. Parts do not come with instructions. OEM Crosman part, pictures enlarged for easy viewing. The mounting holes are 17/32" center to center. I have many other parts listed for these rifles if you are looking for another part you might checkout my store. Thanks,