Extang Tool Box Tonno Truck Bed Tonneau Cover | 32655 | fits Chevy/GMC Silverado/Sierra (8 ft) 07-13, 2014-2500HD & 3500HD, 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