BACKRACK™ hardware kits are available in both no-drill and low profile designs. The new LOW PROFILE DRILL Hardware Kit is available for select late model full-size trucks. These require you to drill two holes through the top of the bed rail for installation. If you must have the Toolbox sitting at bed rail height this is the option. Four carriage head bolts secure the assembly allowing you to place the Toolbox at a low profile using existing clamps that came with the Toolbox. Drill if you must. Not compatible with TONNEAU COVER ADAPTER Brackets.