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