Two indicators in one: monitors 3 and 10 minute flash cycles at 272°F Specifically designed for non-porous and porous loads. After monitoring a 3-minute steam flash sterilization cycle used for a non-porous load, the arrow pointing to the "3" turns from green to dark. After monitoring a 10-minute steam flash sterilization cycle used for a porous load, the arrow pointing to the '10' turns from green to dark. the numbers 3 and 10 also act as a color standard reference.