On some of the new heads like toro, the buttons came with a seat on the underside ,I did not see any on the rainbird, I was curious what the adjusting screw mated up to. Right now we are clearing buttons every now and then, little pieces of debri get lodged in them. With the strainers in place the flow will drop but the pattern will remain uniform when they start to glog. Is that the theory? I don't know why we never used the strainers, I will have to look into it. Thank You