The thickness of {TAIL ~ the thick walled portion} is set to be about 1.4 to 1.6 times the thickness of {HEAD ~ the thin walled portion} 
The thickness of { TAIL ~ the thick walled portion } is set to be about 1.4 to 1.6 times the thickness of { HEAD ~ the thin walled portion }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD