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).
Photographic comparison of standard, palladium coated, and rhodium coated K.L.G. V.II spark plug electrodes.
| Identifier | ExFiles\Box 58\2\ Scan170 | |
| Date | 6th December 1933 guessed | |
| K.L.G. V.II STANDARD. "A". K.L.G. V.II WITH PALLADIUM COATED ELECTRODES. "P". K.L.G. V.II STANDARD. "B". K.L.G. V.II WITH RHODIUM COATED ELECTRODES. "R". | ||