According to the style of reference numbers, it seems that this would be called either the 406 or 407 ATT -- "A" seems to deginate the silver dial, rather than the "N" (black); and the "TT" means Tachymeter / Telemeter scales on the dial.

"R" in the reference number shows us a "Radium" dial, usually with painted Arabic numerals.

Fantastic watch!!

Jeff

+++++++++++++++++++++++++++++

: Thank you so much, Jeff! The case corresponds with the reference
: 406 shown in the 1945 and 1946 Heuer catalogs, but the catalogs
: depict a watch with a black dial. The watch has pushers with
: rounded caps and a case in the same shape as the catalog. The
: 1946 catalog also mentions a reference 407 that is 250 CHF
: whereas the reference 406 is 250 CHF, so perhaps my watch could
: be either one.

: By the way, my watch has a Landeron 13 movement.

: Here are the pages in the catalog:

: http://www.onthedash.com/Guide/_Catalogs/1945_Catalog/page04.jpg

:
: http://www.onthedash.com/Guide/_Catalogs/1946_Brochure/1946Broch03.jpg

: Best regards,
: Eric Wind