Builds that keep the 39 mm Classique profile and make both complications work are the ones worth buying. A moon phase that advances on a real lunar cycle and a power reserve sector that moves as the mainspring winds down separate a replica Breguet 7787BB from a costume watch. Judge a listing on four things: case diameter and thickness, dial texture and printing, how the two complications behave, and the fit and finish of the strap and clasp. The rest, boxes and paperwork included, matters far less.

What the 7787BB Reference Sets as the Target

Reference 7787BB is the white gold version of the Breguet Classique moon phase. It runs a 39 mm round case with a fluted case band, straight soldered lugs, a silvered engine-turned dial, Roman numerals, blued Breguet hands with hollowed tips, and a self-winding movement that drives a power reserve indicator and a moon phase aperture. Thickness sits close to 10 mm.

• Pros of holding to these numbers: the watch slips under a shirt cuff, the dial reads well at arm's length, and the silhouette matches in photos.
• Cons: a thin case demands a thin movement, so the closest replicas cost more and are made in smaller runs.

Use these specs as a checklist when you already know the reference and want to score a listing fast.

Option One: Functional Moon Phase and Live Power Reserve

This tier copies the behavior of the reference, not just the look. The moon disc advances through a proper cycle, and the reserve needle climbs as you wind and drops over the run time. The dial pattern is usually cut rather than printed, and the hands get a heat-treated blue finish instead of paint.

• Pros: the front of the watch holds up under a loupe, you can hand it to a friend without steering the conversation, and it keeps value better within replica trading.
• Cons: the top cost tier, batches come and go, and the added module makes future servicing impractical.

Best for: a daily wearer where you want the complications to be real and the case to stay slim.

Option Two: Real Moon Phase, Painted Power Reserve

Mid tier builds get the eye-catching display right and fake the quieter one. The moon aperture tracks the lunar month, while the reserve arc is printed on the dial and never moves. Dial texture is stamped, so the pattern looks flat under direct light even though it is there.

• Pros: reasonable cost, the moon phase is the harder complication to fake and it is done properly here, and case finishing is usually decent.
• Cons: a static reserve needle is the first thing a knowledgeable eye catches, and stamped dials lose the light play of the original.

Best for: wearing on evenings and in photos where the reserve sector stays small in frame.

Option Three: Look-Alike With Painted Complications

Budget listings sell the shape only. Both displays are static or, at best, a day and night disc that spins every 24 hours. The case runs thick, plating wears at the crown and lugs, and the dial pattern is a flat print.

• Pros: the lowest outlay, and it photographs acceptably from a distance.
• Cons: thickness and dial flatness give it away fast, plating fails within months of daily wear, and the movement is rarely worth repairing.

Best for: a single event or a costume need, not a regular rotation.

Checks That Sort the Tiers in Person

Run the same five tests on any listing before you commit. Wind it and watch the reserve needle move. Watch the moon disc over a week. Turn the case under a lamp and look for cut guilloche with bright ridges. Check that the lugs are soldered straight pieces with screw bars rather than bent spring bars. Compare the thickness against a 10 mm reference point.

• Pros: these tests catch the common failures before money changes hands.
• Cons: none of them predict long-term reliability, and none can be run from a single product photo.

Best for: any buyer comparing two listings at the same price.

One practical caveat: counterfeits of trademarked designs are treated as infringing goods in the United States, and shipments can be seized at the border. That does not change what to look for, but it does affect how a purchase is shipped and what recourse you have if it goes wrong.