The vertical advancing seat is provided with a slide block capable of sliding along {HEAD ~ the vertical advancing seat} in {TAIL ~ the vertical direction} relative to the base 
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The vertical advancing seat is provided with a slide block capable of sliding along { HEAD ~ the vertical advancing seat } in { TAIL ~ the vertical direction } relative to the base
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH