6497 and 6498 — big Unitas pocket calibres on the wrist

In brief

Both calibres came out of the Unitas stable, drawn up for pocket watches rather than for the wrist — which is why they measure 36.6 mm across, enormous for a wristwatch movement. The 6497 and the 6498 differ only in where the sub-seconds sits. That scale, and finishing meant to be looked at, made them the obvious choice for the large-case watches with display casebacks that took hold from the 2000s onwards.

Short history

Unitas ranked alongside Valjoux and Peseux among the big Swiss ébauche houses of the years before all of them were folded into ETA. Its large pocket-watch calibre outlived the pocket watch itself: with barely a change to the architecture, it was recast as a hand-wound wristwatch movement once the fashion for big cases gave it a purpose again.

Why it matters

Much of Panerai's revival from the late 1990s rests on it. Those outsized cases needed a hand-wound calibre on the same scale, and the Unitas/ETA 6497-6498 fitted exactly.

Watches that used it

• Panerai
• Large-case Swiss watches