Something you may want to bring up with the others on your boat is the potential for these devices to damage your boat. Hear me out. I used to use the white plastic clips that you thread the fender whip through. At the end of the sail, I'd just pull them out and hang them on the lifelines. Easy right?
The problem was that over time I noticed that they seemed to loosen my stanchions. A handful of times, I had dock lines either wear through or stolen and the boat ended up against the fenders and dock. The movement of the boat and water put quite a strain on the fenders, thus the lifelines and stanchion tops. Over time I noticed most of the stanchions near where I had been attaching my fender clips had become loose and leaked. Unfortunately my headliner had no access panels so I got to cut out parts of the head liner getting to the hardware so I could rebed the stanchions.
I don't know if others have had similar experiences, but I stopped using them a few years back. I tie to the base of the stanchions now and haven't had a problem since. Just food for thought.