Bio-Compact-PCD®s are special process challenge devices that can be loaded with Mini-Bio-Plus self-contained biological indicators (SCBI). The combination of a gke Steri-Record® Bio-C-PCD® and a Mini-Bio-Plus SCBI is a type 2 indicator according to EN ISO 11140-1. These test systems allow the possibility to monitor sterilizer parameters and penetration characteristics by using SCBI inside a PCD. Six Bio-C-PCD®s with different air removal characteristics are available. The sensitivity of these Bio-C-PCD®s can be selected to meet the requirement of the load. The validation of the Bio-C-PCD®s according to the load can be achieved by using the test method described in DIN 58921.