Referring to FIG 1, the outer fins 2 can be rolled by {HEAD ~ one time} forming on {TAIL ~ outside wall} of a tube body 1 with inner fins 17 to manufacture an enhanced heat transfer tube 
forming on
Referring to FIG 1 , the outer fins 2 can be rolled by { HEAD ~ one time } forming on { TAIL ~ outside wall } of a tube body 1 with inner fins 17 to manufacture an enhanced heat transfer tube
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH