The fingers are movable between {HEAD ~ a retracted position} for {TAIL ~ insertion} into a bag and an extended position in which they can overlap the outer surfaces adjacent to each carton corner 
for
The fingers are movable between { HEAD ~ a retracted position } for { TAIL ~ insertion } into a bag and an extended position in which they can overlap the outer surfaces adjacent to each carton corner
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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