{TAIL ~ The rings} are preferably formed as {HEAD ~ open cylinders} having a series of axially extending slits through the wall thereof 
{ TAIL ~ The rings } are preferably formed as { HEAD ~ open cylinders } having a series of axially extending slits through the wall thereof
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH