A module installable in an electrostatographic printing apparatus includes a first housing suitable for retaining marking material, and extending substantially a width of a rotatable charge receptor. The first housing includes an input port and an output port. The module includes a second housing external to the first housing, the second housing forms a conduit between the output port and the input port. The second housing contains a quantity of marking material, the quantity being suitable as at least part of an initial fill of marking material for the first housing.