Breitling is a Swiss watch company that originally made watches for aviation. They are most commonly worn now as luxury watches, but all Breitlings still feature chronometers that can be used during flight. Breitling first sold the Navitimer in 1952. The Navitimer features a circular slide rule, which can compute all flight plan calculations. Breitling Navitimer replicas are commonly sold online when the buyer cannot see the watch before purchase.
Look at the Breitling logo on the second hand. It will feature the signature "B" and anchor. A genuine Navitimer will have a metal logo on its second hand that is not smudged. On a fake Navitimer, the anchor may be fused into the "B," or the "B" will not appear like it does in the Breitling logo.
Look at the complete Breitling logo under the 12 o'clock position. This logo features the wings, "B" and anchor. None of the features should be fused together. The logo is also slightly raised from the face of the watch. It should not look as if a logo sticker was placed on the watch.
Make sure the chronometer functions properly. Chronograph watches are expensive to make and a replica Navitimer most likely will not have a fully functioning chronometer. There should only be numbers around the outside of the chronograph dials, not days of the week or months.
Turn the watch face down and look at the engraving on the back of the watch. The engraving should be clean and deep. A fake watch will typically only have a stamp or etching of the correct wording on the back of the Navitimer. You will easily be able to tell the difference between quality engraving and a stamping. Consult the Breitling website for a 360-degree picture of what a Navitimer should look like.