...and the cape cod? reminding me somewhat of that 'flying euro'...go figure...page 80:

https://books.google.co.uk/books?id=CAWtAAAAMAAJ&pg=PA258&lpg=PA258&dq=what+does+2M19+mean&source=bl&ots=mdUWoy7j44&sig=p6SP1q1dNUBa6d6aALGihZQPJw8&hl=en&sa=X&ved=0ahUKEwjVwuyY5c7NAhUJJsAKHZ6RByAQ6AEINzAG#v=onepage&q=what%20does%202M19%20mean&f=false