Moog R Series Control Arms With Ball Joint is the right choice for a value-driven replacement part. Moog introduced the R-Series arms to provide replacements for a wide range of domestic and foreign vehicles. The RK Series line of control arms has OE fit and form geometry alignment. The arms with pre-installed OE style bushings mostly include ball joints. These ball joints are not serviceable like the CK arms. All R Series line of control arms are produced as per Moog validated design and construction, providing quality at a less expensive price.