Furthermore, the size of {HEAD ~ the U} shaped cross section of the attachment piece is either substantially equal to or preferably slightly less than the thickness of the headrest base 3 so as to make use of {TAIL ~ its extensibility} to bring the attachment piece into firm contact with the circumferential edge of the headrest base 3 
Furthermore , the size of { HEAD ~ the U } shaped cross section of the attachment piece is either substantially equal to or preferably slightly less than the thickness of the headrest base 3 so as to make use of { TAIL ~ its extensibility } to bring the attachment piece into firm contact with the circumferential edge of the headrest base 3
OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH