Aquanaut

Embossed dial and applied markers

The Nautilus dial has fine horizontal embossing and applied white-gold markers with luminous inlay; a flat printed or grainy dial indicates a fake.

Patek Philippe Seal

Movements since 2009 carry the Patek Philippe Seal (earlier pieces the Geneva Seal). The stamp, plus the reference and case numbers engraved between the lugs, must be crisp and internally consistent.

Hand-finished movement

Expect Geneva striping, chamfered bridges and a gold rotor visible through the sapphire back; rough finishing or an ETA-style movement is disqualifying.