Biological indicators provide the best assurance of sterility by challenging the sterilizer with quantifiable, highly resistant Bacillus stearothermophilus spores. The system includes rapid readout biological indicators, disposable test packs, auto-readers and log books. Biological indicators are used for load control monitoring which is the process by which a load is monitored and released based on the result of a biological indicator (BI) in a test pack. Contains 25 pieces.