The ad says 1955 at the top, but in the description, it says, 1944. Which would be consistent "Not available for the duration".
http://www.ebay.com/itm/1955-HERCUL...age_Hunting&hash=item56673632aa#ht_1837wt_656
I believe the term “for the duration” may have started in the Civil War, and continued through WW2. Volunteers signed up for military service for a specific period, or the duration. This all came about as the Union Army lost Divisions of 90 day and one year Volunteers after their enlistments ran out. I read a book (War from the Inside http://www.gutenberg.org/ebooks/29313) by an Union Officer whose Division went through Bull Run, Antietam, Fredericksburg (shot to pieces before the sunken road), Chancellorsville, and then their term of enlistment ended and they were sent home. This was a massive loss of experienced, trained veteran troops. While I have not researched this in depth, I highly suspect, later on the terms changed to X years or the duration.
http://www.ebay.com/itm/1955-HERCUL...age_Hunting&hash=item56673632aa#ht_1837wt_656
I believe the term “for the duration” may have started in the Civil War, and continued through WW2. Volunteers signed up for military service for a specific period, or the duration. This all came about as the Union Army lost Divisions of 90 day and one year Volunteers after their enlistments ran out. I read a book (War from the Inside http://www.gutenberg.org/ebooks/29313) by an Union Officer whose Division went through Bull Run, Antietam, Fredericksburg (shot to pieces before the sunken road), Chancellorsville, and then their term of enlistment ended and they were sent home. This was a massive loss of experienced, trained veteran troops. While I have not researched this in depth, I highly suspect, later on the terms changed to X years or the duration.