Citizen Original Spare Part – Mainspring – Size 8 ¾''' (1.40 × 0.085 × 245 mm) – NOS (1 Piece)

Original Citizen spare part – mainspring (German "Zugfeder", also winding spring/drive spring, Jap. ぜんまい/zenmai) from unused old stock (NOS). Offered is a single mainspring in original Citizen packaging with the historical "CITIZEN MAINSPRINGS" emblem.

The mainspring is the energy storage of the mechanical movement: wound in the barrel (香箱), it is tensioned via the crown and drives the entire gear train by its relaxation. As a central power source and wear part, it fatigues over time, can take on a permanent set or break – a suitable replacement is part of every overhaul.

Specification (according to original label):

• Size: 8 ¾'''
• Width: 1.40 mm (Dennison thickness 3)
• Thickness: 0.085 mm
• Length: 245 mm

For a movement-true, originality-oriented restoration, a genuine Citizen mainspring in original packaging is the first choice – especially for collectors who want to preserve the original condition of their watch.

The part is unused (NOS) and comes from decades of storage. As with any true NOS part – comparable to original NOS vintage car spare parts – age is part of its authenticity: a stored carbon steel spring may have taken on a slight permanent set, lost some elasticity, or be superficially darkened/slightly corroded. For originality-oriented collectors, this is precisely the appeal – a period-correct original part instead of a modern reproduction. Storage marks may also be present on the foil and packaging.

Manufacturer: Citizen (Citizen Watch Co., Japan). The packaging and logo style roughly date the piece to the 1950s/60s.

Warranty (used)
This is an original part (NOS) stored for decades. The limitation period for defect claims (statutory warranty) is 12 months from delivery.

Note
For those who value originality in a vintage watch – a particularly high standard in the Japanese collector's market – this genuine, period-correct Citizen mainspring is the right choice. Before installation, please check the condition and compare the dimensions (width × thickness × length) and the barrel fit with the target caliber; installation should be carried out professionally.