What does this number measure?
A textile surface covers its rubber shell. Displayed dimension: representative diameter.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Catalogue value to check against the source; not individually audited.
Yellow felt tennis ball.
Model not specified: Varies by period. Proposed historical date; an existing documentary source is linked but was not consulted for this date in this session. Do not interpret this reference as the manufacturing date of the illustrated specimen. Generic ball; several materials, standards and generations exist, with no universally applicable year. A universal year would be misleading.
