Each of {TAIL ~ the guide rails} comprises an end proximate to the aerosol valve and {HEAD ~ an end distal} from the aerosol valve 
Each of { TAIL ~ the guide rails } comprises an end proximate to the aerosol valve and { HEAD ~ an end distal } from the aerosol valve
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH