These upper mono-ball joints are designed to adjust upper control arm angles, allowing you to accurately adjust the roll center. They interchange with the common K-6024 GM upper ball joint. They come complete with mount plate, tapered stud, mono-ball, bushings and nuts. They are available with a flat plate for upper a-arms with minimal angle and an angled plate for upper a-arms with more angle. "WARNING: This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm."