The outer fins 2 wind and extend around {TAIL ~ the outside surface} of the tube body 1 in {HEAD ~ helical manner} 
The outer fins 2 wind and extend around { TAIL ~ the outside surface } of the tube body 1 in { HEAD ~ helical manner }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD