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).
Proposed layout of a foot switch with a specified diameter.
| Identifier | ExFiles\Box 165\1\ img004 | |
| Date | 4th February 1937 | |
| PROPOSED LAYOUT OF FOOT SWITCH 1 11/16 DIA ENS 999 A.H.M 4-2-37 | ||