Redesigned rear lower suspension holder for the REAR of the rear suspension allows use of XB4 arms at rear of XB2 cars. CNC-machined from premium Swiss 7075 T6 aluminum. Ultra-strong construction provides extra-long lifespan and durability in extreme racing conditions. Narrower design increases rear roll while generating more traction.Aluminum lower suspension holders with Integrated Suspension Settings™ (I.S.S.™) allow for quick & easy suspension geometry setting changes. The suspension geometry is completely adjustable using eccentric suspension bushings inserted into aluminum suspension blocks, along with additional suspension shims.