Gally they are okay, but a better way I think, is Rubber or Elastic rope. Put round the back and held in the hand. It seems to give muscle a better idea of what to do, and the body mechanics seem to respond a lot better and more naturally. Another little thing you can try is to attache the rubber round the ring post, or something solid. Then move back throwing punches in clusters with your feet moving as fast as your hands. That will make you punch a lot faster, do 30 sec rounds on it with a 15 sec rest you will feel the difference