The slider has a contact portion in close contact with the inner peripheral wall and positioned upstream of {HEAD ~ the block member} at {TAIL ~ the first position} in the sliding direction 
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The slider has a contact portion in close contact with the inner peripheral wall and positioned upstream of { HEAD ~ the block member } at { TAIL ~ the first position } in the sliding direction
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH