I have a 2 pronged fixed rest, that has adjustable tension, I believe it is a NAP but not for sure, it looks a little older, but I am new to this whole bowhunting thing, i can hit what im aiming, but still learning as I go, how the heck do you adjust one of these things, I mean i know how to adjust the tension, but why would you do this, and how do I know how to adjust it, thank you for any advice and sorry for such a newbish question