Our new LOW PROFILE DRILL Hardware Kit is available for select late model fullsize 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. Vehicle Fitment: Year Make Model 2007-2018 Chevrolet Silverado 1500 2007-2018 Chevrolet Silverado 2500 HD 2007-2018 GMC Sierra 1500 2007-2018 GMC Sierra 2500 HD