This Ruger manufactured second variation 9 round magazine assembly is for the early (pre-A100) Mark I semi-auto pistol with the magazine button flare on the right side of the frame. This magazine is in very good condition with honest wear and a few specks of surface rust. (file photo)

Note: Ruger Mark I semi-auto pistols with the following serial numbers have been observed with this part:

No Prefix: 127144, 129129, 166765 & 210887

10-90939