Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by general context]
6. hardware (components)
7. [hardware by form]
8. finish hardware (hardware)
9. [securing devices and securing device components]
10. securing devices
11. locks (securing devices)
12. [locks by form]

Narrower term/s

• duplex locks
• hotel locks

Anotations

Scope note:

Locking systems intended for use in a series, each lock of which may be actuated by two different keys, one capable of operating every lock of the series, and the other capable of operating only one or a few of the locks.