The 3M™ Attest™ 1261 Biological Indicator (blue cap) is designed for monitoring 270°F (132°C) gravity displacement steam sterilization processes. The presence of active Geobacillus stearothermophilus spores is detected by a visual color change (media turns yellow). The yellow color change indicates a sterilization process failure. The final readout of a negative result (media remains purple) is made after 24 hours of incubation. Indications for Use Use the Attest™ 1261 Biological Indicator to monitor: 1. 270°F (132°C) gravity displacement steam sterilization cycles. Contraindications None.