Mechanical timer needs identifying.

[hangarman]

Not part of the quiz but i'm hoping someone can identify it for me. Came in a screw topped tin made by Metal Box 10, which is what attracted me to it in the first place. It looks like a timer, with a part missing?
Well i'm assuming that its a timer of some description, guessing at British circa 1944, as the tin it came in is dated '44 . Any thoughts anybody??

 

[Bonnex]

Valve, Time, No 1 Mk I, 6 Hr Variable delay for the Marker, Marine, Aircraft, 21 lb Mark III

Also had an SOE interest.

 

[hangarman]

By ek, that was a quick response, Thanks for the info.
What was the soe interest? is it complete?
Cheers
Hangarman

 

[Bonnex]

It is missing the setting gear. I am trying to find a decent drawing but it is not proving to be easy. It features in the RAF Pyrotechnics manual but not with any detail.

The SOE were interested in timers generally for demolition work but I think that this device was used, or experimented with, in connection with supply container dropping but I am not certain. If I find anything out I will let you know.