Cralis that bit you've circled is the prop synch. There's an automatic system to synchronise the propellers. In the B200 there's a Type I and a Type II, but I won't go into the differences now as it isn't really relevant.
The little black and white "spinny thing" is called the synchroscope. It spins when the props rpm is not synchronised. It spins clockwise if the right one is rotating faster, or counter-clockwise if the left prop is rotating faster.
Not that it really means much for this discussion, but you've put up a C90 King Air panel pic.
HOWEVER, I don't quite agree with what Slatye has posted. The AFX system does a much better job than most pilots and it is a fairly robust system in Beechcraft twin turboprops. I've never had them go wrong- but then again maybe there are tightarses out there with poor maintenance who neglect their aircraft and thus take the "it doesn't/might not work very well so I'll just turn it off" stance. That's a topic of discussion for another day!
There's a very simple procedure- when the engine fails you check that it has auto feathered. If not you manually feather it. Takes no longer than let's say turning off the system and planning to do it manually anyway.
It is a very good safety system and, if it's an option, may as well use it.
Megan,
Sorry I missed some of your post earlier re mandatory AFX. I'll have to go digging through my notes to see if I can find it, however my best recollection is that the Hartzell-Raytheon/Hartzell-Raisbeck props require AFX all because of Vmca considerations when they were certified.