A thermal resistor can be provided between {TAIL ~ the outer fin} 2 and {HEAD ~ the tube body} 1 
A thermal resistor can be provided between { TAIL ~ the outer fin } 2 and { HEAD ~ the tube body } 1
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH