The inner cylindrical member 40 has {TAIL ~ an outer shape} and a cross section, as shown in FIGS 3A and 3B. A pair of housing portions {HEAD ~ 40a} for housing the rear cylindrical members 4 are juxtaposed 
The inner cylindrical member 40 has { TAIL ~ an outer shape } and a cross section , as shown in FIGS 3A and 3B. A pair of housing portions { HEAD ~ 40a } for housing the rear cylindrical members 4 are juxtaposed
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH