TripleD the tube is on the duo snap. They put a tube over the line and the Duo snap. The tube is just loose enough to allow the leader to slide. You then just open up the duo snap , which has the clip piece straightened out and most likely they put a point on the end they straightened out. They then just stick the point end through the top and bottom lips of the smelt, Then you just adjust the line to the lenght of the fish, as your trolling the hook just glides along side of the smelt. you can hook the bait in the tail but I guess those guys don't. I would.