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.
