that take a photo knob it's hide on tha attack periscop is not wisible when u hava a crap monitor like me wich suport maxim reso. 1280x1024 (i need to buy another HD one cos 1 it's by my kid computer )u can see that knob only by Obs periscop
this screen it's from fifi and there u can see also on attack periscope cos have a high reso. At Obs. periscope u can see it cos u can hide the TDC on crap monitor