3rd gen Toyota 4 Runner frame stiffeners designed to weld along the frame for added strength. The factory frame was not designed for the lifts and oversized tires that we install today. These stiffeners were designed to increase the life span of your Toyota. Frame stiffeners also help with rust repair for those of you that live where they salt the roads. CNC cut form 10 gauge cold rolled steel. Sold in pairs for driver and passenger side frame rails.