This 5" steel lever style window operator was used on Hehr 9" and 11" model AF French windows. The lever is original Hehr part number 606.
These originally came in 5", 8" and 9" lengths, so please make sure you need the 5" version (measured from where the handle bends to the hole).
Also, note that with this Hehr 606 version, the notches are on the inside of the curve. Some other versions of the lever operators have notches on the outside of the curve.