Aluminum Rear Lower Suspension Holder REAR for semi-split bulkheads offer an expanded range of set-up adjustments. The aluminum suspension holders feature Integrated Suspension Settings™ (I.S.S.) which allows for quick & easy suspension geometry setting. Using eccentric suspension bushings inserted into aluminum suspension holders – as well as additional suspension shims – the XB8 suspension geometry can be completely adjusted in mere seconds. Machined from premium Swiss 7075 T6 aluminum and black coated.