Readylift's 1.5" front strut spacers mount on top of the strut assembly and maintain the smooth OEM ride without adding pressure to any stock components. Constructed of CNC machined Billet aluminum with pressed in 10.9 grade mounting studs for a precise fit. The FX4 F150 has a smaller amount of rake than standard F150's. This kit was designed to level the FX4. It will, however, work on all 2004-12 F150 trucks.