Self-adhesive, non toxic, chemical process indicators change from blue to pink upon exposure to 10 minutes of saturated steam at 121 °C or 2 minutes at 134 °C. Longer exposure will result in a brighter shade of pink. The blue to pink colour transition is sensitive to time, temperature, and the presence of saturated steam.

• Water based ink is made without the use of heavy metals
• Indicators are stable for at least 18 months when stored at room temperature

Exposed indicators are stable and will remain pink when stored under labeled conditions.