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).
Promotional document for the Sparton S.O.S. and S.O.S. Junior horns.
| Identifier | ExFiles\Box 49\5\ Scan122 | |
| Date | 27th November 1925 guessed | |
| The New SPARTON SOS Jr {Mr James Royce} SPARTON S.O.S. Junior. A smaller model, identical in mechanism and design. Price £3 - 17 - 6 SAFETY FIRST SOUND SPARTON The New SPARTON SOS horn | ||