{HEAD ~ The mandrel} is preferably formed of {TAIL ~ a rigid, foamed plastics material} such as a structural foam 
is preferably formed of
{ HEAD ~ The mandrel } is preferably formed of { TAIL ~ a rigid , foamed plastics material } such as a structural foam
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH