What happnes is that the threaded piece screws into the elbow, that protrudes out 1 of the cutouts for the return line. You then attache the loc-line style returns to that. What I had to do was come off the threade piece a short distance and then put the "Y" connector in to bring the return around the front of the overflow. This required the purchase on an extra length of the return tubing.
Be aware that they are not true Loc-Line returns. Look on the pieces to get the name, it escapes me right now. The loc-Line will work, but the joints don't fit together tightly so it doesn't hold it's position well. I ended up zip tying it to my overflow to hold it up.
