I guess many people know that im a newbie in the flying hobby... I have a Superstar MK II it came with an OS .40LA in the manual it is recomended using an 11X7 prop for running in, then says after a good run in period you can use a 10X6, 10.5X6, or 11X7. I was just wondering... What exactly do these numbers mean, I am pretty sure it has to do with the length and pitch of the prop,

If my assumption on lenght and pitch are incorrect what are the numbers, and how exactly is flying affected by these numbers?