TST Control Strip monitors time, steam, and temperature for use in sterilization devices (autoclaves). Changes from yellow to purple provide a visual indicator of a successful sterilization cycle and that all critical autoclave parameters (time, steam, and temperature) have been met. Use at least one in each cycle; can be used in individual trays, packs, or pouches. Suitable for use with the following cycle: 15 minutes at 121°C. Class 6 indicators Package contains 100 pieces