For windsurfing I always used Dakine fixed (no swing) non-adjustable harness lines, so when I wanted adj. harness lines for windfoiling I stuck with fixed so the line would be in the same place when I unhooked/hooked-in in-flight. But due to delivery delays there were none available, so decided to try the Sailworks quicktune lines which swing, and glad I did! They are as light as regular fixed non-adj. lines, have a nice stainless steel V jam cleat (no teeth to wear the rope) with a pulley, can attach without removing the tail, but that requires taking both ends apart (so not like the Ion Varios where the strap comes undone). But the big plus is that I can slide my hand on the boom to the rear strap and easily drop down to grab the adjustment rope, once I have the rope in my hand and either in or out of the cleat it is like having my hand on the boom, so very stable while I adjust the length shorter or longer. And I thought the swing would be a problem, but now I like it since if I lift the hook they swing out on their own, and with a subtle movement of the boom I can swing them into position to grab with the hook. And at $48 are reasonably priced. The clear tubing also allows you to see the rope wear, though the rope looks and feels very durable. The ability to adjust both ends gives unlimited adjustment.