"Instructor One" Ron Holmes and the MantisX

Ron Holmes aka Instructor One tells us what he's learned from using the MantisX

[@CarlosRobertoSuazoArriaga]

I m very exited with this product, is a great one!
I have a question, what does the circle in the target shooting figure mean? Are they MOA? or one imaginary inch at a certain distance?
Thank you!