Glossary
A document some manufacturers, notably Patek Philippe, will issue confirming a specific case and movement number and the watch's original sale details.
An extract is issued against the manufacturer's own production records for that exact case and movement number pairing, which makes it strong supporting evidence, though it confirms what the maker originally shipped rather than the watch's current condition or whether parts have since changed. It complements, rather than replaces, physical authentication.
Browse the full glossary, or look up a serial number in the registry.