For 5 mm leather, here is a great clasp for 5 mm leather. MG120AC is a great pewter magnetic clasp with a ANTIQUE COPPER finish  for using with leather and fabric. As creative as all of you are, we are sure you will find great ways to use this clasp in other applications for making jewerly. Use this magnet clasp to make a wonderful wrap around bracelet or anklet, or mabe even a belt. Check out our other leather findings for making leather jewerly too. We have a great selection of sliders, leather and components.