{TAIL ~ the first trap unit} further includes {HEAD ~ a collection unit} for collecting the debris molten on the surface of the first trap unit 
{ TAIL ~ the first trap unit } further includes { HEAD ~ a collection unit } for collecting the debris molten on the surface of the first trap unit
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH