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