A sterilization process challenge pack including a base tray, a first cover, and a second cover is configured to provide a restrictive flow path for gaseous sterilization medium to test the efficacy of a sterilization process. The base tray includes at least one chamber containing a biological indicator and/or chemical indicator. The first cover including a notch is configured to cover the at least one chamber. The second cover is attached to peripheral surfaces of the base tray except at an unsealed portion. A flow path through the unsealed portion and the notch in the first cover provides the only fluid communication between an external environment and the at least one chamber.