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).
The trial and performance of two-way press button switches on experimental cars.
| Identifier | ExFiles\Box 64\4\ scan0203 | |
| Date | 9th March 1929 guessed | |
| -2- improvements) for trial shortly. The old switches (two-way press button) have been entirely satisfactory, one on 9-EX (32,000 miles) and one on 14-EX (20,000 miles). EFC. | ||