Lightweight yet ultra-strong rear upright molded from unique INTENSE composite product. Features bigger outside 8x16x5mm ball-bearing for increased dependability and life-span. Makes the trunk of car very stable. Improves bump taking in and handling in hotter conditions. Fits XB8, XB8E, GTX8'19 and much more present, GTX8E'19 and more recent, XT8'19, XT8E'19