A nozzle assembly comprising: a hollow nozzle body having a central blind bore and a plurality of ports (110, 112, 114) extending through the body from the central blind bore; and a switching valve cartridge disposed in the central bore operable to direct fluid flow from an inlet to at least one of the plurality of ports (110, 112, 114) upon application of fluid flow above a predetermined threshold to the inlet and direct fluid flow from the inlet to at least a different one of the plurality of ports (110, 112, 114) upon fluid flow having subsequently dropped below the predetermined threshold and then exceeding the predetermined threshold, the cartridge comprising: cylindrical cartridge case having a front portion and a cup shaped rear portion; cylindrical poppet slidably disposed within the cup shaped rear portion of the cartridge case; a guide cooperating with the poppet to alternate fluid flow between the ports, wherein the guide includes one or more guide members engaging the poppet to alternatingly align the poppet with the at least one of the plurality of ports (110, 112, 114) and the different one of the plurality of ports (110, 112, 114) each time the poppet abuts the front portion of the case; and characterised by a biasing member within the cartridge case between the front portion of the case and the poppet urging the poppet away from the front portion of the cartridge case, wherein each transition below the predetermined threshold causes the poppet to rotate to permit fluid flow to alternate between the at least one of the plurality of ports (110, 112, 114) and the at least one different one of the plurality of ports (110, 112, 114). a hollow nozzle body having a central blind bore and a plurality of ports (110, 112, 114) extending through the body from the central blind bore; and a switching valve cartridge disposed in the central bore operable to direct fluid flow from an inlet to at least one of the plurality of ports (110, 112, 114) upon application of fluid flow above a predetermined threshold to the inlet and direct fluid flow from the inlet to at least a different one of the plurality of ports (110, 112, 114) upon fluid flow having subsequently dropped below the predetermined threshold and then exceeding the predetermined threshold, the cartridge comprising: cylindrical cartridge case having a front portion and a cup shaped rear portion; cylindrical poppet slidably disposed within the cup shaped rear portion of the cartridge case; a guide cooperating with the poppet to alternate fluid flow between the ports, wherein the guide includes one or more guide members engaging the poppet to alternatingly align the poppet with the at least one of the plurality of ports (110, 112, 114) and the different one of the plurality of ports (110, 112, 114) each time the poppet abuts the front portion of the case; and characterised by a biasing member within the cartridge case between the front portion of the case and the poppet urging the poppet away from the front portion of the cartridge case, wherein each transition below the predetermined threshold causes the poppet to rotate to permit fluid flow to alternate between the at least one of the plurality of ports (110, 112, 114) and the at least one different one of the plurality of ports (110, 112, 114). cylindrical cartridge case having a front portion and a cup shaped rear portion; cylindrical poppet slidably disposed within the cup shaped rear portion of the cartridge case; a guide cooperating with the poppet to alternate fluid flow between the ports, wherein the guide includes one or more guide members engaging the poppet to alternatingly align the poppet with the at least one of the plurality of ports (110, 112, 114) and the different one of the plurality of ports (110, 112, 114) each time the poppet abuts the front portion of the case; and characterised by a biasing member within the cartridge case between the front portion of the case and the poppet urging the poppet away from the front portion of the cartridge case, wherein each transition below the predetermined threshold causes the poppet to rotate to permit fluid flow to alternate between the at least one of the plurality of ports (110, 112, 114) and the at least one different one of the plurality of ports (110, 112, 114).