| System | Period | Rows | What it dates |
|---|---|---|---|
| Wilkinson Sword — stamps and lines (Pall Mall → Empire) | a safety razor from 1898; Empire 1930–c. 1950; 7-Day Empire 1936–1952 | 6 | Wilkinson razors have no direct serial numbers/date codes: the key is the line (Pall Mall / Empire), the blade type (removable wedge), the self-stropp |