Reinforcing strips are used between bed cross sills on longbeds, fleetsides and some stepsides. These reinforcment strips are slightly shorter than the cross sill and are bolted to the bed strips and angle strips only. These strips reinforce the bed, but do not attach to the frame of the truck. The holes in the reinforcment strip determine the placement of the bed strips and wood. Sold each. Fits trucks with fleetside bed with wood floor.