This Linhof parallel mirror alignment tool TKPA is supplied in a somewhat distressed factory box (solely because a previous owner taped it shut).  Used in conjunction with a device that rests on the enlarger baseboard (not supplied) for the precision alignment of Linhof 4x5-inch format enlargers, it may also be useful for aligning other equipment.  Showing only slight signs of having been handled, it's possible this tool was never actually used.  Robustly constructed and uncommon.