Answer first
A fake Breguet Type XXI 3817 is a copy of reference 3817ST/X2/3ZU, a 42 mm stainless steel flyback chronograph. Genuine examples trade in the five-figure range. Replicas sell from about $150 to $700 depending on tier. Five details decide whether a replica is worth its price: the fluted caseband, the dial texture, the 24-hour day/night subdial, the flyback reset, and the caseback engraving. Check those five points and ignore most of the marketing around them.
What the genuine 3817 looks like
The Type XXI 3817 is a Transatlantique chronograph in a 42 mm steel case with sapphire on both sides. The caseband carries the coin-edge fluting Breguet uses across the Type XX and Type XXI line. Inside sits a self-winding flyback chronograph with a running seconds subdial, a 24-hour day/night subdial, and a date aperture. The pushers flank the crown at 3 o'clock. Water resistance is rated to 100 m. The dial is a grey plate with a fine guilloché pattern, printed with the brand name and the reference text.
Replica tiers you will see
- Budget, $120 to $250: quartz or low-grade automatic, stamped dial pattern, plated case, printed caseback text.
- Mid, $250 to $450: automatic movement with a decorated rotor, correct subdial layout, mineral or sapphire front crystal.
- Top, $450 to $700: flyback-capable clone movement, sapphire front and back, cut fluting, closer fonts on the dial print.
Inspection checklist
- Turn the watch face down and run a fingernail along the caseband. Genuine fluting is cut metal with sharp ridges. Replicas often show soft molded lines.
- Tilt the dial under a lamp and watch the pattern shift. Real guilloché moves with the light. A stamped dial stays flat.
- Compare the subdial indices and the date aperture against the case center line. Any tilt shows up here first.
- Start the chronograph and let it run for 20 seconds. Press the lower pusher while it runs. A true flyback resets and restarts in one press. A standard chrono stops.
- Flip the watch and read the caseback with a loupe. Look for even engraving depth, correct reference digits, and a serial number that matches the paperwork.
- Weigh two replicas of the same model side by side if the seller allows it. A hollow case reads lighter than a solid steel case of the same size.
Movement checks
Ask for a photograph of the movement through the caseback before you pay. High-grade finishing shows Geneva stripes with clean edges, polished screw heads, and rotor engraving with visible depth. Low-grade clones show stamped plates, uneven plating, and shallow text. Spin the rotor by hand and listen. A dry rattle points to a cheap movement. Press the chronograph reset a few times and confirm the hand lands at 12 with no drift.
Questions for the seller
- Which movement is inside, and who made it?
- Is the crystal sapphire or mineral, front and back?
- Is the flyback function real or decorative?
- What is the return window, and does it cover a movement fault?
- Can you send photos of the actual unit, not stock images?
Mistakes buyers make
- Buying on dial photos alone and never checking the caseband or caseback.
- Assuming a sapphire caseback means a decorated movement. Many low-grade clones hide a plain plate behind glass.
- Paying top-tier money for a quartz movement in a steel case.
A practical note on branding
Watches that carry a live trademark name are treated as counterfeits at many borders and can be seized in transit. A first copy that reproduces the logo carries that risk. If the look matters more than the label, choose a hommage build with no brand text on the dial or caseback. You get the same case shape and layout with none of the customs exposure.