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).
Table of specified gaps for the new duplex push button switch.
| Identifier | ExFiles\Box 64\3\ scan0277 | |
| Date | 5th July 1926 | |
| To BY/RD. from EFC. X7650 EFC2/T5.7.26. X.7650. DUPLEX PRESS BUTTON SWITCH. Herewith we hand to you copy of table of specified gaps in connection with the new duplex push button switch. Would you kindly arrange your instructions to the Expl. Shop accordingly. EFC. | ||