The header can have a thickness substantially less than the probe diameter and can comprise {HEAD ~ a flange} about {TAIL ~ an edge} of the header 
about
The header can have a thickness substantially less than the probe diameter and can comprise { HEAD ~ a flange } about { TAIL ~ an edge } of the header
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 OTH OTH OTH