Photograph displaying four lever arms with their associated ball bearing components.
| Identifier | ExFiles\Box 41\1\ Scan111 | |
| Date | 4th July 1929 guessed | |
| ", | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).