A refill component is provided for a multi-part sterilant system including a pump head having a peristaltic pump member, a first-part dispensing tube and a second-part dispensing tube. The refill component comprises:a first part comprising a first reagent in a carrier medium in a first collapsible container;a second part comprising a second reagent in a carrier medium in a second collapsible container;wherein the first reagent and the second reagent will react to provide a sterilising composition when the first part is mixed with the second part.Each container (80) is secured to a collar member (78), the collar member (78) having, for each container, an opening which is aligned with an opening of the container (80) to receive a corresponding dispensing tube from a pump head. The open end of each container (80) has a neck portion (84) and a lip (86), and each opening in the collar member is dimensioned to support the lip (86) of a container (80) and has a slot portion (82) which extends to an edge of the collar member (78) for slidably receiving the neck portion (84) of a container (80).