When it comes time to replace the upper ball joints in your Zone Offroad upper control arms these ball joints are a quick and easy swap. This master kit Includes one (1) ball joint with nut, red anodized aluminum dust cap, O-ring, grease zerk fitting, cotter pin, and snap ring (where applicable) designed for use in the C2300, C2312, C2313 and C2314 upper control arms.