[Little Miss Purple]

I don't have a great idea of how to actually set the button (my partner does it!!) but I do know when you lose the screw and subsequently the spring - the arrows go flying off to the left and out comes the metal detector. I was lucky in that a fellow club member had a spare button (another lesson learned!), once in place the right hand side of the arrow sits on the left hand side of the string as you look at it in line. Hope that made some sennse to you!