ReadyLIFT SST series Jeep JK Wrangler Control Arms feature Heavy-Duty DOM tube steel construction with fixed ends featuring the new Terrain Control Technology Flex Joints at both ends. These joints require NO servicing and provide increased joint flex with NO inner bushing bind during articulation. Not only does this increase the life of the TCT joint, but it also increases the amount of joint flex required during heavy-duty off-roading without compromising the comfortable OEM-like ride on the streets. The SST upper control arm feature adjustability to dial in axle position and caster. Bolt on installation - No modifications required.