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