A separator tube for {HEAD ~ insertion} into a collection tube comprises a tubular member having {TAIL ~ one end} closed by a plug 
A separator tube for { HEAD ~ insertion } into a collection tube comprises a tubular member having { TAIL ~ one end } closed by a plug
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH