In the preferred embodiment of the invention, the flat annular surface 34 at the tip distal end lies in a plane positioned at {HEAD ~ an angle} of {TAIL ~ 15°} to a plane normal or perpendicular to the center axis of the tip 
of
In the preferred embodiment of the invention , the flat annular surface 34 at the tip distal end lies in a plane positioned at { HEAD ~ an angle } of { TAIL ~ 15 ° } to a plane normal or perpendicular to the center axis of the tip
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 REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH