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