Class 6 TST indicator steam emulating test strips. Monitors sterilisation process to ensure proper completion. Economical: the strips are perforated in the middle, so each strip can perform 2 tests - 100 strips equals 200 tests. Colour changes to green after successful completion: 3.5 mins at 134°C and 15 mins at 121°C. Conforms to ISO 18472 and HTM 01-05 compliant.