PartsW 4 Pc Suspension Kit for Ford Expedition F-150 F-250 Lincoln Blackwood Navigator Upper Control Arms & Lower Ball Joints Control Arms Come Pre-Assembled With Ball Joints & Bushings / Replacement improves handling Advanced corrosion protection against the harshest conditions / Precision-made performance and additional strength Designed with PREMIUM quality materials for exceptional performance, reliability and peace of mind Dust boot is re-installed and permanently attached to reduce contamination, and increase durability and service life Premium alloy steel stud for strength and durability / Undergo impact, wear, and fatigue testing to help ensure quality and durability