Knowledge Center

Professional Authentication Platform

Log InRegister

Universal Genève 138SS

Probable

The first Polerouter caliber, in production in the watch for only a matter of months from autumn 1954 before the micro-rotor 215 replaced it. Its practical significance for authentication is behavioural: a bumper knocks audibly and palpably as the weight strikes its buffers, so the caliber generation can be identified through a closed case.

Specifications

Movement manufacturer
Universal Genève
Production
?–1955
Winding
automatic

Architecture

Bumper automatic: the winding weight travels through an arc rather than rotating fully, striking sprung buffers at each end of its travel.

Authentication notes

  • MovementProbable

    The knock identifies the caliber without opening the watch

    Move the watch and feel the winding weight arrive at the end of its travel. A bumper delivers a distinct, repeatable knock; a micro-rotor turns silently. Since the dial spelling must agree with the caliber generation on this line, this is half of the brand's cleanest consistency check and it costs nothing.

Related calibers

References using this caliber

Provenance of this record

Sources & Evidence

Secondary sourceSpecialist publication

Specialist horological writing on Universal Genève, the Polerouter and the micro-rotor

Established horological publications and dealer research

Accessed
2026-08-19

Cited for

This referenceProbable

Last verified: Not yet reviewed