Never underestimate the importance of a small part. The Line Retainer does just what its name implies; it "retains" the bowfishing line in a safe location before you shoot. Use it between every shot. If your line is loose between your Retriever and your bow, it can get hooked around your Trigger Assembly when you draw back and literally tear your Retriever apart when you shoot. But, if you push the line into your Line Retainer and keep the line tight to your Retriever, you will protect your equipment and yourself. (Line Retainer Bushing and 1" Screw sold separately).