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