O-ring seal for the receiver drier on Mk5/Mk6 VW models & 8P Audi A3 TDI. There are TWO of these on the drier, so order TWO if you are replacing both seals. Most driers come with at least one seal, so if you are replacing the drier you may only need one.
(All the driers IDParts sells include two o-rings, so you do not need to order additional seals.)