Two models are available the Checktemp 2 and 3 meters which are pocket thermometers with the unique built-in calibration check device and a folding 110mm long probe - designed to fold at different angles for measurement in difficult places. The calibration check is achieved by simply clicking a switch, which is housed within the battery compartment - if the unit is in calibration the LCD will display 0.0°C. Highly accurate, these meters display temperature in °C from -20.0 to +120.0°C with an