Steam sterilization indication ink is used to test steam sterilization effects.When the steam's temperature in a disinfection cabinet is within 121℃to135℃, the color of the label made of this ink turns from white to black, showing to what extent the sterilization process is completed. The changing of the colors lasts for about 3-4 minutes.There are other color available: Blue-to- Black, Yellow-to-Black.