This Rack Kit is for truck canopies/camper shells/caps and trailers that have roof top sizes no larger than approximately 1345mm/53'' (W) x 1358mm/53.5'' (L). The Slimline II Tray mounts to six (6) supplied Feet that slide in to the supplied Track. The 1500mm/59.1'' long pair of tracks can be easily mounted to your canopy/shell or trailer.See the Track installation instructions in the INSTALL tab for further details.