{HEAD ~ The insert} & fins are held in {TAIL ~ place} by use of grub screws which screw through the receptacle at an angle and apply pressure to the insert and fin together 
are held in
{ HEAD ~ The insert } & fins are held in { TAIL ~ place } by use of grub screws which screw through the receptacle at an angle and apply pressure to the insert and fin together
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH