The GKTECH Polyurethane rear knuckle bushing replacements are designed to replace the OEM upper arm bushings on the knuckle side. These are required when removing the ball joint from a HICAS equipped knuckle however can also be used to replace the OEM rubber bushings for camber and traction arms also. These are designed to be used on the knuckle side only and can not be used elsewhere. Vehicle Compatibility: - Nissan S13 240sx - Nissan S13 Silvia - Nissan S14 240SX - Nissan S15 Silvia - Nissan Skyline R32 GTS-T - Nissan Skyline R32 GTR - Nissan Skyline R33 GTS-T - Nissan Skyline R33 GTR - Nissan Skyline R34 GTT - Nissan Skyline R34 GTR - Nissan C33 - Nissan C34 - Nissan C35 - Nissan A31 Cefiro Fits all S/R chassis OEM rear knuckles with 30mm O.D, most rear knuckles are this size but we do recommend measuring before purchasing.