Citizen PHINOX Mainspring – NOS Original Mainspring for Citizen · Size 10½ / 11½ (Center Third / Center Second) · 1 Piece (NOS)

NOS Mainspring from original Citizen workshop stock, Series "PHINOX - Citizen" with the classic Citizen "C" logo. We are offering one single piece (1 unit) from an original dozen box ("1 Dozen").

This mainspring is intended as a historically correct original replacement for vintage Citizen movements and is ideal for restoration and service.

Technical Data (Manufacturer's box specifications):

• Brand/Series: Citizen PHINOX
• Purpose: for Citizen
• Size: 10½‴ / 11½‴, Type 中三 (chū-san = central second, three-hand with small/central second hand – "center-seconds three-hand")
• Original box content: 1 dozen (here sold per piece)

Note on measurements: I do not have a specification label (品質規格) for this box, therefore exact details on thickness (厚さ), width (幅), and length (長さ) are not available. These can be added before listing if required, either from the label or by measuring the mainspring.

About the brand / material:
The box bears the designation "PHINOX" – a spelling variation of the mainspring material "Phynox" that Citizen used in this series. Both refer to the same high-quality cobalt-chromium-nickel alloy (Co-Cr-Ni). This cobalt-chromium-nickel alloy offers a combination of high strength, ductility, and good mechanical properties, is hardenable, has excellent fatigue resistance, is corrosion-resistant, and non-magnetic. Phynox is also known under the names Elgiloy, Conichrome, and Alloy 3J21.

Thus, this mainspring belongs to the category of modern "white metal" mainsprings, which, in contrast to classic blue carbon steel, are rust-free and practically unbreakable, and retain their elasticity. Citizen deliberately marketed its original mainsprings – similar to Swiss manufacturers with "Nivaflex" – under the premium alloy name. It is therefore a Citizen original part. The nostalgic box graphics also make the piece a decorative collector's item from the golden age of the Japanese watch industry.

Scope of delivery:
1 piece "Citizen PHINOX" mainspring (single piece from original box). Photo shows representative box and mainspring example; a single mainspring will be delivered.

Warranty (used)
This is used goods (New Old Stock from old inventory). The statutory warranty is shortened to 12 months.

Note
Due to its age, no guarantee is given for the function or unused elasticity of the mainspring.