ISV control module: from what model?

[Konstantin Bogach]

Hi.

I have spare ISV control module 443 907 393M.  But I don't know what
model it is from. But I know it is type44.  Anybody recognize the number
and, especially, "M" at the end?
Do modules with different letters at the end interchangable?

Thank you.

Konstantin Bogach.