Bilstein SZ Series shock absorbers feature a 46mm piston, steel construction and smooth body designed for motorsports applications. These shock absorbers are available in a variety of lengths and standard digressive valve settings that utilize proprietary spring steel valve discs and can be converted to a coilover design (kit sold separately). They are also available as dry kits (partially assembled wtih no valving or gas) that are geared towards giving tuners the versatility to build to their unique needs. SZ Series shock absorbers are ideal for racers whose sanctioning rules do not allow or require rebuild capability.