This complete zipper pull sets contains shells, metal backs, black plastic versa backs, and metal zipper pulls. This allows you to hang a finished button off a zipper! A cool way to display your flair! Just load your button making machine like normal with the metal back positioned with the hole at the top. Then insert the versaback into the hole in the finished button. Attache the pull to the top of the versa back and grip that zipper with gusto!!