The short answer
"Fake Ballon Bleu 33708" is a search term for a replica of the Cartier Ballon Bleu. The number 33708 is a case-back stamp. Cartier does not sell a watch called 33708. The stamp shows up on case backs of Ballon Bleu watches, and sellers use it to describe the case family. A replica sold under this term copies the 42 mm Ballon Bleu: round steel case, domed bezel, crown guard with a blue cabochon, guilloché dial.
Replica quality runs from rough to close. The gap sits in the dial finish, the cabochon, the movement, and the case-back engraving. Below is what to compare.
What the 33708 stamp tells you
The stamp sits on the case back next to the serial and the water-resistance line. It marks a case and movement combination, not a full model code. Cartier catalog references use a different format, such as W69012Z4. Sellers mix the two. Ask for the catalog reference and photos of the case back before you compare prices.
Case and crystal
Genuine 42 mm Ballon Bleu: about 42 mm across, about 13 mm thick, polished steel with a domed bezel that wraps the crown. Lug width and curve matter. Low-tier replicas get the case profile close but leave the bezel edge too sharp.
Crystal: sapphire on the genuine watch. Low-tier replicas use mineral glass. Tap tests and edge reflections are weak tests. Ask the seller to name the crystal.
Dial and hands
The dial carries a flinqué guilloché pattern that radiates from the center. Replicas print the pattern or stamp it shallow. Under a loupe, printed texture looks flat and the lines stop short of the numerals. Roman numerals need crisp black transfers that sit inside the tracks. Hands are sword shaped and blued. Replica hands run thick at the tip.
Cartier hides a "CARTIER" signature on many dials. Check for it with a loupe. A missing or shifted signature is a clear tell.
Crown and cabochon
The crown sits inside a steel guard and carries a blue synthetic spinel cabochon. Genuine stones show depth and a dark navy tone. Replica stones read bright blue, sit flat, and show glue at the base. Run a finger over the cabochon. A ridge or a loose stone fails the check.
Movement and case back
Genuine 42 mm automatic uses Cartier caliber 049, built on an ETA 2892-A2 base. Replicas use a Miyota 9015, a Seagull, or a clone of the 2824. A Miyota beats at 28,800 vph and runs well. A cheap 21,600 vph movement with a noisy rotor does not.
Case back: check the screw heads and the engraving depth. Real engraving cuts deep with clean edges. Laser marking shows a grey, shallow line and a wrong font weight.
Bracelet and clasp
Steel links should move with no rattle at the joints. Screw heads should sit flush. The clasp logo should be cut, not stamped into a soft plate. Replica bracelets show burrs on the inner links and loose spring bars.
Price bands and what they buy
- Under $150: mineral glass, printed dial, 21,600 vph movement, glued cabochon.
- $250 to $450: sapphire, stamped guilloché, Miyota or clone 2824, better cabochon.
- $500 and up: closer case profile, deeper engraving, better dial texture. Still a replica.
Checks before payment
- Ask for the catalog reference and a photo of the case back.
- Ask which movement and which crystal.
- Request a macro photo of the dial center and the cabochon.
- Confirm the return window in writing.
- Pay with a method that reverses a charge.
Legal note
Replicas copy a protected trademark. US Customs can seize shipments. Selling counterfeits is a crime in the US. A buyer gets no Cartier service and no warranty, and a seized parcel means a total loss.