In {HEAD ~ this instance}, the movement of {TAIL ~ the slider} 20 is smoothly carried out irrespective of the holding means 34, because of the relief 30 
In { HEAD ~ this instance } , the movement of { TAIL ~ the slider } 20 is smoothly carried out irrespective of the holding means 34 , because of the relief 30
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH