Not quite #3
These are nicely made screws - nicer than as shown in the photo. However, they are not truly #3s. They are closer to #2s. Their shanks are too thin to grab well in an existing #3 hole, and their threads are not correctly spaced either. In addition, the small size continues to the screw's head, which will not fill a countersink previously bored for a true #3. Therefore, as replacement/restoration screws these maybe quite inadequate, but in new applications, they may work satisfactorly. Beware, the screws come with a blackened finish of some sort, not raw steel as suggested by the photo.

