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).
Page two of a document detailing the order status for Cobra horns for models 20-EX, 21-EX, 22-EX and 23-EX.
| Identifier | ExFiles\Box 113\3\ scan0022 | |
| Date | 20th November 1928 guessed | |
| PAGE TWO. 4. 20-EX, 21-EX, 22-EX and 23-EX. Cobra horns are on order from the makers but have not yet been received. Cx{Major Len W. Cox - Advertising Manager}/Hn.{F. C. Honeyman - Retail orders} [Signature] | ||