I work at the Computer History Museum in Mountain view, CA

http://www.computerhistory.org/

In our punch card section, we have 3 IBM 026 Keypunches.

When you lift the cover of the print portion of the keypunch;

This is the size of the actual ribbons;

We also have an IBM 029 keypunch that uses the same ribbon;

Box of NOS keypunch Ribbons;

3/16 = .1875

The box you sent me shows;

The ribbons you sent me are 12.7 mm wide.

The box of ribbons you sent me are for some IBM printer but not for the IBM Keypunches.

I will be expecting a full refund soon.

Stan Paddock