Seiko Spare Part - Winding Stem for Seiko Caliber 4N21 (1 Piece) - NOS

Original Seiko Winding Stem (巻芯) from new old stock (NOS) for the Seiko Caliber 4N21. Offered is a single piece, in the original SEIKO bag (handwritten "4N21 / 巻芯").

The winding stem is necessary for winding and hand setting: The square engages with the setting mechanism, the external thread accommodates the crown.

Regarding caliber assignment: The 4N21 caliber belongs to the Seiko "4N" family of small movements; the corresponding Seiko winding stem is listed in parts catalogs as reference 351155 (common for 4N00/4N01/4N20/4N21/4N70/4N71).

The part is unused; due to storage, minor, purely cosmetic traces are possible, but these do not affect the function.

Note on assignment: Before installation, please compare dimensions, thread, length, and square with the required winding stem or your own movement.

Manufacturer: Seiko (K. Hattori & Co., Japan).

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 Before installation, please compare dimensions and fit with the required winding stem; installation should be carried out professionally.