Polerouter

Polarouter and Polerouter are different watches, not spelling variants

The A-spelling belongs to the first series only — the Polarouter name lasted a few months and the watches carrying it were built across 1954 and 1955, all on the bumper caliber 138SS. The check is ASYMMETRIC and it is important to get the direction right: a POLAROUTER dial over a micro-rotor is an inconsistency requiring explanation, usually a redial or a swapped dial. But a POLEROUTER dial over a 138SS bumper is FACTORY-CORRECT — the first watches to carry the new name kept the bumper caliber, and the movement changed to the micro-rotor 215 shortly after the name did, not simultaneously with it. Treating that combination as a fault would condemn a genuine early Polerouter, which is among the more desirable versions of the watch.

A bumper announces itself

The 138SS is a bumper automatic: the winding weight travels through an arc and strikes sprung buffers at each end, producing a distinct knock felt through the case as the wrist moves. A micro-rotor turns continuously and silently. An examiner can therefore tell which generation of Polerouter they are holding before opening anything, which is worth doing precisely because the dial spelling has to be checked against it.