Proline Biological Indicator System is designed for use in the validation or monitoring of sterilization cycles of tubing ranging from 1/8� to 5/8� tubing ID. The ProLine PCD (Process Challenge Device) contains a filter paper disc inoculated with bacterial spores of Geobacillus stearothermophilus (for Steam) or Bacillus atrophaeus (for EO). The spore disc is packaged in a glassine envelope and is located in the center of the ProLine housing. If adequate sterilant penetration occurs, the spores on the disc will be deactivated and verify an adequate sterilization cycle.