Cross-section drawings comparing K.L.G., Lodge, and A.C. spark plugs.
| Identifier | ExFiles\Box 27\3\ Scan260 | |
| Date | 19th October 1941 | |
| K.L.G. GAS TIGHT SEAL LODGE GAS TIGHT SEAL A.C. GAS TIGHT SEAL CAST IN SILVER CORE PROMOTES THERMAL CONDUCTIVITY FIG. 2. JTOA / 19.10.41 | ||
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).