- Authentic Patek Philippe watches will be have crisp and evenly spaced printing, free from misspellings. - Apart from skeletonized models, real Patek Philippe watches do not have a visible tourbillon or balance wheels on the dial. - All modern Patek Philippe watches use sapphire crystals.

Certain Patek Phillipe models have a reputation for being great investment choices, such as the Nautilus, Aquanaut, Calatrava, and Grand Complications. Two specific models that are highly sought-after with prices that appreciate well over time are the Nautilus 5711/1A and the Aquanaut 5167/1A-001.

Patek Philippe Aquanaut Price Guide: How Much Does an Aquanaut Cost? The cost of a Patek Philippe Aquanaut ranges from $23,000 to $47,000 for time and date models, $40,000 to $73,000 for complicated models, and $21,000 to over $200,000 for ladies' gem-set models – if you buy them at retail.

Reference and serial numbers should not be visible on a Patek Philippe watch's caseback, and faux versions will often have model or serial numbers visible on the caseback. Exhibition casebacks, however, are another story. Serial and calibre numbers may be visible on timepieces with exhibition casebacks.