The short answer
A "fake Patek Philippe tourbillon 5304" is a replica watch styled after Patek Philippe's ref. 5304 Grand Complication, a platinum piece built around a minute repeater and a perpetual calendar. The copies sold under that name are cosmetic tributes. Some have an open-heart cutout or a spinning cage meant to read as a tourbillon. Almost none of them chime, and none of them carry a Patek movement. So the price gap between a $180 copy and a $900 copy comes down to case finishing, dial printing, and how honest the seller is about the movement inside.
What the genuine 5304 actually is
Patek's own 5304 belongs to the Grand Complications family. The point of the watch is mechanical: a minute repeater that strikes the time on gongs when you slide the lever, paired with a perpetual calendar that tracks the date, day, month and leap years without correction. Patek set a sapphire dial over the top so you can watch the hammers and gongs work, which is the whole reason the reference looks the way it does.
That sapphire dial is also why the watch gets misfiled online. People see the exposed mechanics, assume a tourbillon, and search for a tourbillon that isn't there.
Why "tourbillon" ends up in the name
Two things are going on. First, the 5304 is frequently confused with sibling references in the same family, including the 5316, which does combine a minute repeater, a tourbillon and a perpetual calendar. Sellers copy the wrong label and it sticks. Second, a lot of replica listings use "tourbillon" loosely for any visible rotating part, including an open-heart balance wheel. If you are shopping this reference, treat the word as a description of what the listing looks like, not what the watch does.
What a replica 5304 can and cannot do
- It can copy the case shape, the platinum-colored finish, the dial layout and the general weight on the wrist.
- It can add a skeleton dial that shows gears, and a plate that imitates the exposed movement of the original.
- It cannot strike the hours, quarters and minutes on tuned gongs.
- It cannot run a true perpetual calendar with a leap-year cycle.
- It cannot hold finishing anywhere near Geneva standard, because hand-bevelled steel and black polish are labor, and labor is what the real watch costs.
What I check on any replica 5304
- Thickness. A repeater movement is a stack of parts. If the case is slim and flat, there is nothing inside doing the work.
- The repeater slide. On a fake it is usually fixed, or it moves and does nothing. Ask the seller to record the sound.
- The calendar displays. Look at whether the subdials actually change at midnight or sit frozen.
- Dial printing. On a 5304 homage the text is often too bold, spaced wrong, or glued under a flat mineral crystal.
- Caseback screws and engravings. Laser etching looks shallow and white next to a deep stamp.
Where the copies give themselves away
Mostly at the edges. Case flanks that should be polished and crisp go soft. Lugs taper differently. The sapphire dial, if there is one, looks cloudy instead of clear. Weight is another tell, since the original is platinum and most replicas are steel with a coating. If a listing claims a real tourbillon, a real repeater and a real perpetual calendar for a few hundred dollars, the math does not work at any factory on earth.
The legal side, briefly
US Customs and Border Protection treats counterfeit goods as seizable, and importing them is a violation regardless of what the listing says about shipping.