An optional Front Air Bump Kit adds race-proven 2-inch-diameter hydraulic bumpstops as a secondary suspension, to improve off-road comfort and durability. The Poly Performance upper towers and lower mounts are engineered to be compatible with common body lifts, engine lifts, on-board air systems, and aftermarket suspension systems. The JK Coilover Conversion Kit is supplied as one complete system or two individual sections (Front Kit and/or Front Air Bump Kit).