{HEAD ~ a counter tool} placed in {TAIL ~ opposition} to the sonotrode to define a gap there between for passage of the material web 
placed in
{ HEAD ~ a counter tool } placed in { TAIL ~ opposition } to the sonotrode to define a gap there between for passage of the material web
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH