Wanted-Drafting machine rulers (Roseville)

Wanted, rulers for a drafting machine, 12-inch, 18-inch, 20 inch or other sizes.
These have a metal clip on one or both ends, they attach to the L-shaped part of the machine.
The measurements on them might be inches, millimeters, centimeters or some numbers that you might find on an architect's scale.
Some brands are Keuffel & Esser, Alvin, Vemco or Mutoh.
They are mostly interchangeable.
Thanks for looking.