Extang Tool Box Tonno Truck Bed Tonneau Cover | 32645 | fits Chevy/GMC Silverado/Sierra (5 ft 8 in) 07-13 works with/without track system 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