An exhaust mixer apparatus comprising: an exhaust conduit configured to extend in an elongate direction comprising an inlet and an outlet for transporting exhaust fluid; a first exhaust mixer comprising: a plurality of elongate mixing blades each having a length extending in the elongate direction, the elongate mixing blades connected together along at least part of their lengths and arranged about the elongate direction, each elongate mixing blade comprising an outer edge extending in the elongate direction, wherein the elongate mixing blades are twisted along their lengths such that the outer edge of each elongate mixing blade is rotated about the elongate direction, and the exhaust conduit is configured to locate the first exhaust mixer in an upstream location of the exhaust conduit ; and a second exhaust mixer configured to impart a swirl on an exhaust fluid when in use, the second exhaust mixer arranged in a downstream location of the exhaust conduit downstream and spaced apart from the first exhaust mixer in the elongate direction, characterised in that the first exhaust mixer and the exhaust conduit further comprise a plurality of co-operative locating tabs and a plurality of co-operative locating slots configured to fixedly locate the elongate mixing blades relative to the exhaust conduit ; the exhaust conduit comprising the plurality of co-operative locating slots and each elongate mixing blade of the first exhaust mixer comprising at least one of the plurality of the co-operative locating tabs ; and the exhaust conduit comprising first and second conduit portions configured to define the plurality of co-operative locating slots when connected together. an exhaust conduit configured to extend in an elongate direction comprising an inlet and an outlet for transporting exhaust fluid; a first exhaust mixer comprising: a plurality of elongate mixing blades each having a length extending in the elongate direction, the elongate mixing blades connected together along at least part of their lengths and arranged about the elongate direction, each elongate mixing blade comprising an outer edge extending in the elongate direction, wherein the elongate mixing blades are twisted along their lengths such that the outer edge of each elongate mixing blade is rotated about the elongate direction, and a plurality of elongate mixing blades each having a length extending in the elongate direction, the elongate mixing blades connected together along at least part of their lengths and arranged about the elongate direction, each elongate mixing blade comprising an outer edge extending in the elongate direction, wherein the elongate mixing blades are twisted along their lengths such that the outer edge of each elongate mixing blade is rotated about the elongate direction, and the exhaust conduit is configured to locate the first exhaust mixer in an upstream location of the exhaust conduit ; and a second exhaust mixer configured to impart a swirl on an exhaust fluid when in use, the second exhaust mixer arranged in a downstream location of the exhaust conduit downstream and spaced apart from the first exhaust mixer in the elongate direction, characterised in that the first exhaust mixer and the exhaust conduit further comprise a plurality of co-operative locating tabs and a plurality of co-operative locating slots configured to fixedly locate the elongate mixing blades relative to the exhaust conduit ; the exhaust conduit comprising the plurality of co-operative locating slots and each elongate mixing blade of the first exhaust mixer comprising at least one of the plurality of the co-operative locating tabs ; and the exhaust conduit comprising first and second conduit portions configured to define the plurality of co-operative locating slots when connected together. <EOS>