The casing body may be provided on {HEAD ~ both sides} thereof with reliefs which serve to prevent the holding members from interfering with movement of {TAIL ~ the slider} 
The casing body may be provided on { HEAD ~ both sides } thereof with reliefs which serve to prevent the holding members from interfering with movement of { TAIL ~ the slider }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL