Radio measurement module with one built-in NTC temperature probe; 868 MHz When using ECOLOG-PRO 1NTR in a temperature range between -35 °C and -10 °C, please source two pieces of lithium-metal batteries (AAA) locally and place them into the device. Lithium-metal batteries are not included. Two alkaline batteries included. Production Calibration Certificate, including 3 points electrical calibration (-35 °C, 0 °C, +50 °C) and 3 calibration points in thermal bath (0 °C, +15 °C, +25 °C), can be easily downloaded here: