This pair of Ruger manufactured fifth variation checkered black synthetic grip panels with hollow backing and silver phoenix factory medallion is for the late variation Mark I semi-auto rimfire pistol with the grip frame marked "A-100" and the magazine button flare on the left side of the frame. This pair of grip panels are in very good condition with light wear. (file photo)

Note: Ruger Mark I semi-auto pistols with the following serial numbers have been observed with this part: 12-72207, 16-58723 & 17-33228