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).
Modification drawing for a Wraith oil level indicator.
| Identifier | ExFiles\Box 138\2\ scan0131 | |
| Date | 28th March 1938 guessed | |
| WRAITH, MOD. TO OIL LEVEL INDICATOR, E50264, E50271, K4407, Mill 1.500 Dia, .3125 Dia, .5000 Dia, 3 BA, 3 BA FSW, TURN .210 Dia. MILL .150 Dq | ||