An open end bladder 1, in which {HEAD ~ the center} of {TAIL ~ curvature} of a curved portion which is the joint of the corner and the first oblique portion is located inside said bladder; the center of curvature of a curved portion which is the joint of said first oblique portion and the second oblique portion is located outside said bladder; and the center of curvature of the convex portion curved and extending outward from the second oblique portions and constituting the maximum diameter portion of said bladder is located inside said bladder 
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An open end bladder 1 , in which { HEAD ~ the center } of { TAIL ~ curvature } of a curved portion which is the joint of the corner and the first oblique portion is located inside said bladder ; the center of curvature of a curved portion which is the joint of said first oblique portion and the second oblique portion is located outside said bladder ; and the center of curvature of the convex portion curved and extending outward from the second oblique portions and constituting the maximum diameter portion of said bladder is located inside said bladder
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH