The outer fins 2 can be formed by making {HEAD ~ the material} on the tube body 1 extend outward along {TAIL ~ radial direction} of the tube body 1, and can be integrated with the tube body 1 
extend outward along
The outer fins 2 can be formed by making { HEAD ~ the material } on the tube body 1 extend outward along { TAIL ~ radial direction } of the tube body 1 , and can be integrated with the tube body 1
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH