The March 1947 E. Leitz New York instruction sheet 1320-3 discusses the operation of the #66742 ADFIK Adjustable Lens Sunshade and Filter Holder. 34mm unmounted filter glasses could be mounted into the divisible assembly. The ADFIK is engraved Leitz New York, uses millimeters (mm) to denote focal length, and was catalogued as late as November 1951.
The Leitz Wetzlar FIKUS is usually marked in centimeters (cm). The Viewfinder Volume 33, #4, 2000, page 17 shows a very late specimen engraved mm. Leitz New York also made the FIKUS with mm markings. The illustrations show the Leitz New York ADFIK and FIKUS. Editor Rosauer and I welcome your comments.