| Clue | Source | Date |
|---|---|---|
| In the version patented by Johann Nepomuk Maelzel, these wind-up timing devices have settings from 40 to 208 | The Times Specialist Sunday | 13 Aug 2023 |
| Music timekeepers | ||
| Music timekeepers | ||
| Beat keepers | ||
| Musical timekeeper | ||
| Instruments for Horowitz | ||
| Time keepers | ||
| Timekeepers. |