Sterling Watch Mainspring – For Newmark 10½”’, 1.75 x 0.12 x 265mm

Sterling Guaranteed Watch Mainspring – For Newmark 10½”’ – Height 1.75 mm – Force 0.12 mm – Length 265 mm – British Made NOS

Description:
Vintage Sterling Guaranteed Watch Mainspring, supplied for Newmark 10½ ligne wristwatch movements. Produced by Sterling of England, this mainspring offers consistent power, long service life, and reliable timekeeping for British and Swiss wristwatches of the mid-20th century.

Specifications:

• Brand: Sterling

• For: Newmark 10½ ligne movement

• Height: 1.75 mm

• Force: 0.12 mm

• Length: 265 mm

• Marked: “British Made – Sterling Guaranteed”

• Material: Tempered spring steel

• Condition: New old stock (NOS), unused, supplied with original wax envelope

Condition Note:
This is new old stock (NOS) — unused and complete with its original wax-paper packaging. The packaging shows minor creasing and light ageing, and the mainspring may show slight surface tarnish from long-term storage.

Summary:
Original Sterling mainspring for Newmark 10½ ligne movements, Made in England, ideal for restoring vintage British or Swiss wristwatches. A genuine NOS part from a respected mid-century manufacturer.

Shipping:
As usual, this item will be packaged carefully and dispatched with tracking. International shipping is available through the eBay Global Shipping Programme (GSP).