Each one of the two or more individual endless belts of each unit is made of {TAIL ~ a relatively soft and elastic material}, or is padded or covered with foil material, such as {HEAD ~ latex} 
Each one of the two or more individual endless belts of each unit is made of { TAIL ~ a relatively soft and elastic material } , or is padded or covered with foil material , such as { HEAD ~ latex }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD