Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Tools and Equipment (hierarchy name)
5. equipment
6. [equipment by process]
7. image-making equipment
8. photographic equipment
9. photographic accessories

Anotations

Scope note:

Devices used to steady the head of photographic sitters when long exposures are necessary for formal portraits, to prevent blurring the image. These have been rendered mostly obsolete as photographic technologies have advanced.