A sterilization process challenge device comprising a first container comprising walls which define a first space within the first container; a process indicator within the first space; at least one sterilant access for a sterilant to enter the first space within the first container; wherein at least one of the walls which defines the first space is a flexible wall; and wherein the walls are impervious to the sterilant; a method of using the device; and a kit including the device are disclosed.
