Both the seating rim and the seating recess can be of a polygonal shape, with the seating rim fitting the shape of {HEAD ~ the seating recess} of {TAIL ~ the sample changer} 
of
Both the seating rim and the seating recess can be of a polygonal shape , with the seating rim fitting the shape of { HEAD ~ the seating recess } of { TAIL ~ the sample changer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL