You are buying a complete REAR seal and piston kit enough for (2) Calipers to fit AUDI See Compatibility List for Full Details For models fitted with LUCAS/GIRLING TRW single 38mm diameter piston calipers Where pistons contain internal components it is necessary to retain all the internal components from your old piston and refit into the new shell. In most cases this will involve removing the existing Circlip or Snap-ring to withdraw the mechanism, before re-fitting into the new Piston.
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