XVA Series - Suspension Shock AbsorberBilstein XVA Series shock absorbers features aluminum threaded body construction designed for motorsports applications. The large volume dual zone nitrogen bulb, with optional base valve (sold separately), allows for lower gas pressure for increased grip. These shock absorbers are available in non , single and double adjustable configurations for precise on vehicle tuning options. Pistons, piston bands and heims are sold separately to allow the