{HEAD ~ Once hollow closed end needle} 10 has been inserted into {TAIL ~ place} in flexible closed end sheath 4 stopper 26 is slid over hollow closed end needle 10 in the direction of button 25 until teeth 27 and 28 grip around cylindrical surface 31 of element 32 a of button 25 
{ HEAD ~ Once hollow closed end needle } 10 has been inserted into { TAIL ~ place } in flexible closed end sheath 4 stopper 26 is slid over hollow closed end needle 10 in the direction of button 25 until teeth 27 and 28 grip around cylindrical surface 31 of element 32 a of button 25
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH