{TAIL ~ The undercut groove} 323 extends from {HEAD ~ the second end surface} 312 b to the vertical notch surface 318 b 
{ TAIL ~ The undercut groove } 323 extends from { HEAD ~ the second end surface } 312 b to the vertical notch surface 318 b
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH