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