This can only be a user problem. But I found these rectangular clips very difficult to use. The tension must be strong with such products, but goes far beyond that. Since the clamps are not very large, SUCH high tension makes them very difficult to use. And while this may be obvious to most, I was surprised at how limited the size of the items you use them on can be. I just couldn't do it. Maybe someone else was luckier and smarter than me at using them more efficiently. But I personally will probably never use them again.