However, in variations of the tip distal end surface 34, the annular surface may be positioned at an angle to the normal plane ranging between {HEAD ~ 30°} and {TAIL ~ 5°} 
However , in variations of the tip distal end surface 34 , the annular surface may be positioned at an angle to the normal plane ranging between { HEAD ~ 30 ° } and { TAIL ~ 5 ° }
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 HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL