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