This sensor is suitable for monitoring a wider range of temperatures from -200°C to 150°C (-328°F to 302°F). Used for ultra-cold shipments, such as the mRNA based COVID-19 vaccines from Pfizer and Moderna. The Ultra Cold Temperature Sensor is based is an RTD type sensor (Resistance Temperature Detector) made from Platinum. As temperature changes so does the resistance of the metal. This is precisely measured to give a temperature reading. The accuracy of the sensor is ±0.2°C (±0.4°F).