Basically JJ they are movement blanks,supplied to watch brand makers,like
for instance Panerai.They use a ETA Valjoux movement in most of there watches.This was supplied in a blank form with just the small makers stamp like a small hallmark on the inside of the movement. Panerai then done any mods to the Ebauche. And then put there own name Panerai, plus a Panerai movement number, on the finished movement.
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