{TAIL ~ A groove} is formed in an endpiece head to allow {HEAD ~ distal ends} of the head to flex away from the lens and reduce the pressure on the lens 
{ TAIL ~ A groove } is formed in an endpiece head to allow { HEAD ~ distal ends } of the head to flex away from the lens and reduce the pressure on the lens
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH 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