Includes 2 Rear High-Strength Steel Lift Blocks with Built-In Bump Stop PlatesIncludes 1 Brake Line Relocation Bracket to Secure Stock Lines Firmly in Place1-Piece CNC Formed Steel Frame, Laser Cut and Bent to Exact SpecificationsPrecision Welded Using Heavy Duty GMAW Seam & Fillet Welding ProcessesShot Blasted and Powder Coated to Prevent Oxidation & RustReinforced Structure with a Double Wall of 1/4" Thick CNC Plasma Cut Plates3/4th Dual Pins Specific for F-150 Models to Ensure Stability & Easy InstallationBuilt-In Bump Stop Plates to Help Maintain Proper Suspension Travel and GeometryLAB Tests have shown these blocks can withstand an astonishing load of almost 60,000 lbs with no yielding or deformation observed!PLEASE Note:?? 4WD Models come with 1.5" Rear Factory Blocks Pre-Installed. Our Lift Blocks can NOT be stacked and are designed to replace the 1.5" OEM Blocks on 4WD models, resulting the advertised additional rear lift.We are proud to introduce our NEW US Patent Pending Steel Lift Blocks for lifting the rear of your vehicle. Using Heavy Duty GMAW Seam and Fillet Welding Processes we machined each lift block from 1-Piece CNC Formed Steel Frame and reinforced it's structure with 1/4" Thick CNC Plasma Cut Support Walls for maximum strength and stability.These Heavy Duty lift blocks are fabricated with Built-in Bump Stop Plates to help maintain proper suspension travel and geometry, as close to factory specification as possible. This eliminates the risk of bottoming out & improves the quality of your ride while protecting your vehicle’s suspension.Our 4", 4.5" and 5" Tall Lift Blocks are engineered and designed with a Built-In Taper to help keep your differential's pinion angle as close to factory specification as possible. This helps eliminate the possibility of driveline vibration occurring due to misaligned driveshaft/differential angles, and keeps your u-joints and driveline bearings lasting longer.NOTES:An alignment is always recommended after altering the height of your vehicle.Longer U-bolts are required for installation - NOT included in this kit.