A guide 1, {TAIL ~ wherein said housing} unfolds to facilitate installation onto said track at any point along the length of {HEAD ~ said track} 
A guide 1 , { TAIL ~ wherein said housing } unfolds to facilitate installation onto said track at any point along the length of { HEAD ~ said track }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD