Bilstein 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 greatest flexibility in upgrade combinations. XVA Series shock absorbers are ideal for racers looking for an aluminum rebuildable design with multiple upgrade options and superior performance.