Panerai Radiomir An attck diver's important German navy watch with original leather strap on one side and original buckle. So far less than 80 watches of this type are known to exist. Ref. 3646 / Typ D, Cal. 618 / Typ 1, Case No. 260656, Dimensions 47 x 47 mm, circa 1944, Origin Swiss Case: steel, screw back, winding crown and winding stem are missing. Dial: blackened, inlaid and sunk luminous Arabic numerals/indexes, blued luminous baton hands. Movm.: Manual. Both, the cushion shaped case and the plexi are unpolished and in fantastic original condition. The blued steel hands appear untouched, with the original luminous material, partially broken out on the minute hand. The watch has a matching flat bezel, which is characteristic of the Officine Panerai "Radiomir", reference 3646 with brass dial. The inner caseback bears the typical Rolex SA hallmark, reference and case number known for 3646 / Type D watches. The outer caseback of the watch has no personal engravings of the first owner. It remained in a drawer during the last decades and has never before been presented at an auction! This watch is described and illustrated in detail at: www.vintagepanerai.com/2021/03/29/a-3646-type-d-kampfschwimmer-at-dr-crotts-104th/. Watches of the Reference 3646 / Type D are featured in the book "Vintage Panerai - The References 1930's-1940's" by Ralf Ehlers & Volker Wiegmann in chapter II.IV (page 398-531) including a historic photo of a "Kampfschwimmer" wearing a 3646 with brass dial on page 475. In this part of the book, an overview of different decorative polish on the inside of the caseback (Type A –Type G) can be found on page 486. Radiomir Panerai Because of the 1914 invention of the luminous material "Radiomir" - a mix of zinc sulfide and radium bromide - the Panerai dials could be read well at night and in deep water. Panerai made use of this advantage in his watches and was commissioned to produce the first diver's wristwatches, called "Radiomir". The first prototypes were still produced at Rolex, the later watches and their cases were produced at Panerai according to Oyster standards. In 1936 the Panerai Radiomir became a part of the secret naval equipment. Source: "Armbanduhren Klassik Katalog", Koenigswinter 2005, page 146. With the kind support of Ralf Ehlers & Volker Wiegmann, www.vintagepanerai.com, the highly recommended website for vintage Panerai watches. Case: good, worn, lacking elements. Dial: very good, oxydized. Movm.: very good, to be restored. Case: good, worn, lacking elements. Dial: very good, oxydized. Movm.: very good, to be restored.