Complicated how to figure out exactly how to tighten them but I think my husband can help. Don't buy these for anything but leather - I have fabric and manmade shoes and they don't work on those.  These are just about exactly what my memaw had in her closet that I used to be fascinated with - that was 30 some odd years ago, technology hasn't changed that much.  I am generally happy with my purchase.  I will figure them out.