As described above, since the metallic parts 11 and 21 will automatically roll to assume the transverse position, what is more advantageous is that the metallic parts rotate of themselves relative to each other until the flanges extend along the curve of the body, so that the clasp snugly fits on {HEAD ~ the curve} of {TAIL ~ the body} 
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As described above , since the metallic parts 11 and 21 will automatically roll to assume the transverse position , what is more advantageous is that the metallic parts rotate of themselves relative to each other until the flanges extend along the curve of the body , so that the clasp snugly fits on { HEAD ~ the curve } of { TAIL ~ the body }
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 HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL