The machine comprises {HEAD ~ a pair} of {TAIL ~ rollers} at least one of which is driven between which the snake can be clamped so as to drive it toward a plumbing cleanout tool into which the snake is to be inserted 
of
The machine comprises { HEAD ~ a pair } of { TAIL ~ rollers } at least one of which is driven between which the snake can be clamped so as to drive it toward a plumbing cleanout tool into which the snake is to be inserted
OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH