{HEAD ~ The beads} may be made of teflon, polystyrene, {TAIL ~ polyethylene}, or any other suitable particulate material that absorbs vibration energy when vibrated to cause rubbing between the beads 
{ HEAD ~ The beads } may be made of teflon , polystyrene , { TAIL ~ polyethylene } , or any other suitable particulate material that absorbs vibration energy when vibrated to cause rubbing between the beads
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH