The Upper Control Arms (UCA) are an upgraded version of the original parts and are perfectly compatible with the original wheels. Replaced better OEM control arms that lift the vehicle 2-4 inches.Perfect to replace your old or broken car control arm,wear-resisting durable and undamage,No drilling and cutting required,All parts have been preassembled,Easy to install.The front upper control arm with ball joint assembly is made of high-strength steel with solid mounting bracket. Unparalleled strength and durability, no welding weakness.The anti-corrosion coating on the control arm of the upper limb before 2-4 "lifting can prolong the service life and prevent rust. Important Notice All the zerks can fill in grease after some use (pre-greased when you get it)Do not torque the zerk too tight and It can turns to different directions(not must vertical)---the right and left zerks no need to the same directionsThe ball joint could not fill any grease. If you have any problem, please ask us firstly, we will try our best to help you resolve the problem. Measuring Guide Measure your stock front and rear heights from the ground to bottom of the trim. The style of level or lift will determine how much height you will need to add to the front or rear. To level your vehicle, add a lift amount equivalent to the difference between front and rear heights.To lift your vehicle - while retaining the stock look, add the same lift amount to both front and rear.To level lift your vehicle, add the amount of lift you'd like for the front to the difference between front and rear stock heights and use this for your rear lift.For example: if your stock height for the front is 23" and rear is 26" to level - add 3" lift to the front or to lift all corners 2" - add 2" to both front and rear. Feature: Perfect to replace your old or broken car control armProvide more professional ball joint designCorrect the ball joint angle for 2-4” front leveling kitsUnparalleled durability and strengthNo drilling and cutting required Note: Please confirm whether the control arm is suitable for your vehicle before ordering Professional installation is strongly recommended