Apparatus 7, in which {HEAD ~ each tube} is extruded to form {TAIL ~ separate integral ducts} each adapted to house a strand 
is extruded to form
Apparatus 7 , in which { HEAD ~ each tube } is extruded to form { TAIL ~ separate integral ducts } each adapted to house a strand
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH