Backside anti-roll club for ball-bearing roll club mounting system works with back suspension system arms. The anti-roll club system is set up toward straight back bulkheads via bearings from outside for extra-smooth motion and for fast & easy alterations and modification. The roll bar turns in ball-bearings for maximum accuracy and free motion. Anti-roll club height is adjustable via a screw... fast & easy. Anti-roll club has laser-engraved stripes (corresponding to club depth) for easy recognition. May be used with #303434 Aluminum Anti-Roll Bar Bushing o2.0mm - 6mm (2) Fits X4 & X4F