The ThermaGuard Fridge Thermometer is a high accuracy fridge freezer thermometer that is available in two models for varying sensor needs. Essential for food safety, the max/min, alarm and CalCheck functions make this model a great option for HACCP compliance.The internal sensor (101 model only) measures temperature over the range of -19.9 to 49.9 °C, while the external sensors measure over the range of -39.9 to 49.9 °C. Both have an accuracy of ±0.4 °C and a resolution of 0.1 °C/°F. With a 25000 hour battery life (normal use, without alarm) the 1.5 volt AA batteries will only need changing every 34 months. The digital fridge thermometer incorporates a large LCD display which simultaneously displays the current and max/min recorded temperatures. Both models also feature programmable alarms to give you an audible warning if the temperature of your fridge or freezer falls outside the safe temperatures you set.Each ThermaGuard is housed in a splashproof IP54, ABS case which includes Biomaster antimicrobial technology that reduces bacterial growth, ideal for monitoring chilled and frozen foods. An optional two-point (-18, 0°C) UKAS Certificate of Calibration is available. Each certificate indicates deviations from standards at -18 and 0 °C. *UKAS certificate applies to remote probes only. The ThermaGuard 101 incorporates two temperature sensors; a remote water resistant temperature probe with a one metre PVC lead for monitoring the appliance temperature and an internal sensor for the room temperature. The ThermaGuard 102 incorporates two remote water resistant probes, both with one metre PVC leads for monitoring two appliances. Each remote probe can be mounted onto the internal wall of the fridge using the small ABS plastic mounting bracket supplied. Both models of the ThermaGuard features a CalCheck 0.0 °C (?0.1 °C) function that allows the user to verify the accuracy of the thermometer at any time, giving confidence that measurements are accurate.