Heading 9112 covers cases for any goods of Chapter 91, which includes not only wall and mantel clocks but also instrument-panel clocks, time switches, parking meters, and other timing apparatus. The key test is whether the device itself falls within Chapter 91; if so, its case belongs here.

The chapter notes define watches by movement size and portability; cases designed to house watch-sized movements go under heading 9111, while cases for larger clock movements or other Chapter 91 timing devices go under 9112. When the movement size is ambiguous, the intended movement type and the physical dimensions of the case are the deciding factors.