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