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