Got an AR builders kit and will be needing the proper tools unique to AR builds. I don't mind spending for quality and I hate buying junk. Any and all suggestions and recommendations are appreciated.
I believe that number should be 40 FOOT pounds.Lower Receiver Extension (Buffer Tube):
Carbine: Tighten the castle nut to 40 INCH pounds +/- 2 inch pounds.
In your first pic, the box labeled "Flash Hider Wrench", the cutout you point to is actually designed to tighten the A2 rifle buffer tube to the lower receiver.