Not exactly sure what you're asking! shark clips are used for all sorts of things, from a quick method to attach a buoy to a rope, holding "things" in cars, boats and camping, and even what they were designed for, clipping droppers to a main line when pro fishing, that said, I kind of doubt most rec fishers would actually use them for fishing?
I use mine for my fish scaling bag, and berley cage, crab pot lines......... they are very strong and soo easy to use I am just surprised that the likes of BCF and other well know tackle stores dont have them in stock.