Longines 'Nautilus' Skin Diver Wristwatch, Ref. 6921-1

Technical characteristics

Type

Diving wristwatch

Bezel

Bidirectional rotating graduated to 60 minutes

Caliber

19AS

Dimensions

40 mm x 13.5 mm

Case Material

Stainless steel

Place recorded

Switzerland

Model Reference

6921-1

Maker / attribution

Longines

Case Style and Maker

EPSA compressor-style

Design

Dial and Hands

Direct visual observation reveals a black dial exhibiting significant mottled aging and patina across the surface. The dial features luminescent Arabic numerals at the 12, 3, 6, and 9 cardinal positions, paired with a broad-arrow hour hand, a baton minute hand, and a center seconds hand. The seller describes the dial as a lacquered surface and reports the luminous material on the numerals and hands to be radium. No independent radiometric test or laboratory report is provided in the source to confirm this composition.

Visible features

• Black dial displays significant mottled aging and patina across the surface. • Luminescent Arabic numerals at 12, 3, 6, and 9 paired with a broad-arrow hour hand, baton minute hand, and center seconds hand. • External bidirectional rotating bezel with deep edge serrations, dot minute graduations, and Arabic numerals at 15, 30, and 45. • Mounted on a dark brown textured scale-pattern strap.

Identity and Case Construction

The watch is identified by the dealer as a Longines Skin Diver reference 6921-1, designated 'Nautilus' and attributed to 1958. It features a stainless steel case described as an EPSA (Ervin Piquerez S.A.) 'compressor'-style construction. Dimensions stated by the seller are 40 mm across excluding the crown and 13.5 mm in total thickness including the crystal. Front-facing observation shows an external bidirectional rotating bezel with deep edge serrations, dot minute graduations, and Arabic numerals at 15, 30, and 45. The seller states that the case has a screw-down caseback with a logo and that both the case and movement are signed and numbered; however, rear and internal markings are not visible in the provided photo.

Reported Movement and Production Context

According to the seller, the watch is powered by a self-winding Longines caliber 19AS movement with central seconds. While the seller notes that the movement is signed and numbered, the internal mechanism is not pictured in the listing. The listing reports that this reference was produced in limited runs from 1958 to 1960 totaling approximately 500 pieces. Specific movement and case serial numbers are not recorded in the source text, leaving archival production records unverified.

Identification

Reference

6921-1

Source note

Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.

Catalogue references

No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.