Oysterquartz Mark 1 17000 — Pre-COSC Single-Line Dial

The earliest dials, from before the movementMovementThe working mechanism inside a watch or clock. was chronometerChronometerA watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph.-certified: no “Superlative ChronometerA watch or movement certified for timekeeping precision under a defined testing standard. The applicable certification depends on its maker and period; it is not the same as a chronograph. Officially Certified” text, so the dial carries only three lines with “Oysterquartz” alone at six. Blue examples of this period sometimes age to purple.