In preferred embodiments of the invention, iron is mixed as the main component of the material of the spring band clip with {HEAD ~ other elements} in {TAIL ~ a ratio} according to the following table: 
In preferred embodiments of the invention , iron is mixed as the main component of the material of the spring band clip with { HEAD ~ other elements } in { TAIL ~ a ratio } according to the following table :
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH