Extang Tool Box Tonno Truck Bed Tonneau Cover | 32725 | fits Ford Super Duty Long Bed (8 ft) 99-16 L-Channel Rail Bridges the Toolbox-To-Tonneau Gap For Perfect Fit L-Channel Rail also provides a seal against the box Toolbox Tonneaus Fit Most Standard Size Toolboxes, 18-20" Exclusive And Patented All-Climate Tarp Design Adjustable Snaps and Bows For Easy Use In Cold Weather