the ballast rail comprises {HEAD ~ a collet} for securing the ballast rail to the housing for providing enhanced heat sink effects for {TAIL ~ the ballast} attached to the ballast rail, 
the ballast rail comprises { HEAD ~ a collet } for securing the ballast rail to the housing for providing enhanced heat sink effects for { TAIL ~ the ballast } attached to the ballast rail ,
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 OTH OTH OTH OTH OTH OTH