Upgrade your XRS Bed Cross Rail Kit with additional 4-CORE rails that bridge the uprights on both sides of your truck bed. 37 3/4-inch and 49 3/4-inch, although either can be cut down to desired length. The 4-CORE system is an extruded track system that works with any 1/4x20 hex bolt or Quick release clamps. Works with both mid-size and full-size XRS Bed Cross Rail Kits (5935000T/5935001T)