A connector element for connecting a pump assembly for use in a selective catalytic reduction system to a reagent supply of reagent fluid, the connector element comprising: a reagent flow passage arranged to receive reagent fluid at a first end from the reagent supply and to supply the reagent fluid via a second end to a reagent inlet port for reagent fluid on the pump assembly; a coolant passage for cooling fluid, the coolant passage arranged to be in communication with a coolant port on the pump assembly.