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