Bombthrower Mk1/Mk1A

[marco]

Hello all,

I wonder if someone can tell me something about the smoke grenade launcher fitted on many armoured vehicles.

The British version of it is known as "Bombthrower MkI(A)" and the US build version is known as "Bombthrower M3"

Which company's build these weapons?

Some of the launchers were fitted with an exhaust valve with 3 settings in order to be able to adjust the range to 50, 100 or 200 yards.
My manual shows the launcher without the exhaust valve, so the question is: Was the exhaust valve a later modification?

Best regards,

Marco