Find the maker’s name and the complete serial number before starting your search.
Look for a brand name or logo engraved on the instrument. Keep the spelling exactly as marked.
Include any letters or leading zeros. Check easily confused characters such as O and 0, or I and 1.
A model name and a serial number serve different purposes. Keep both if you find them.
Check the maker’s instrument-specific documentation for the marking location. Avoid forcing or disassembling parts to look for it.
Keep a note of the characters you can read. An incomplete number may be insufficient to date the instrument reliably.
Recheck the brand and characters. A missing result can also mean the relevant production period is not covered by the archive.