MARCONI Air Ministry (A.M.) D Type Morse Key. 10F/7373.
The classic MARCONI Air Ministry (A.M.) "D Type" Morse Key, 10F/7373. This is a large ground station key with large contacts and was typically used in RAF control towers during wartime and immediate post war operations.
This key has a massive shiny bakelite overcover, frequently missing or chipped but definitely not so for this example. The reason for the overcover is that the key typically interfaced with the high voltage portion of circuitry in a transmitter, therefore the unit is fully enclosed to protect the operator.
In operation, the rear set of contacts are normally closed and the front set are normally open. By depressing the key the rear contacts open and correspondingly, the front closes. This key is fitted with a screened lead itself terminated with a standard 6mm Jack plug.