Biological indicator vials are easy to use and interpret with visual colour readout in 48 hours. Self-contained biological indicators significantly reduce possibility of contamination, minimizing false positives and assuring more accurate results. Designed for monitoring the steam sterilization process, 3M™ Attest™ Biological Indicator for 121°C/250°F Gravity and 132°C/270°F Vacuum Assisted Steam Sterilizers provides a 48 hour readout.