[Leica] Leicaflex SL instruction

[Claude Serquet <claude.serquet@actant.com>]

Dear all,

I've just got a Leicaflex SL camera which belonged to my late father.
Unfortunately the instruction's manual has been lost, and even if the
general functions of the camera are clear, I don't understand what the
purpose of the disc over the film sensitivity button is. Could someone
explain it to me or at least direct me to a source for instruction
manual, preferably in Europe.

Thanks in advance

Claude Serquet