Identification of these??

[Chris Suslowicz]

Actually, they're part of the Lamp, Signalling Daylight, xxxx Range, and are the "hands-free" torch used by the operator (so he can see to read the message form). (xxxx can be "Short", which is powered by 12 volts worth of dry cells, or "Long", which has a larger lamp (5", I think) and uses a 10 volt lead-acid battery.)

It should have a few feet of (usually fabric covered) flexible cable with a 2-pin plug on the end that connects to the main unit.

The hook is to attach it to a coat/tunic button.

There's one here, in the middle of the second photo.

Chris.