The cable holder has {TAIL ~ two side walls} and a bottom wall, with grooves at the tops of {HEAD ~ the side walls} 
The cable holder has { TAIL ~ two side walls } and a bottom wall , with grooves at the tops of { HEAD ~ the side walls }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD