This Rack Kit is for truck camper shells and trailers that have roof top sizes no larger than approximately 1165mm/45.9'' (W) x 954mm/37.6'' (L). The Slimline II Tray mounts to four (4) supplied Feet that slide in to the supplied Track. The 750mm/29.5'' 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.