Aluminum reduced suspension holder the BACKSIDE of this back suspension redesigned combined with the brand new HS bulkheads for an expanded range of set-up alterations. The rear suspension system holders enable installation in upright or inverted orientations, resulting in extra roll center areas the internal hinge pins. The downward orientation of this suspension holder is employed mainly for Dirt tracks. The upward orientation for the suspension system owner is employed mainly for Carpet tracks. The suspension holders enable usage of both long or standard suspension supply configurations. Machined from premium Swiss 7075 T6 aluminum and black coated. Fits XB4'21