Power supply 2 AA alkaline batteries, 1. 5 VInputs Telephone activator CT3MA and separate temperature probeElectric connections Screw clamps 3. 5 mm twopole jack plugDouble InsulationProtection IP20Micro-disconnection 1BUSoftware Class ATemperature regulation range 2 °C – 40 °CAnti-freeze temperature regulation range 2 °C – 7 °CMax. temperature T45Reference thermal gradient 4 K/hRelative humidity displayed value 20% – 90%Pollution degree 2Impulse Voltage 4000VElectric featuresContacts rating:– 5(3)A 250Vac – CH150 version– 16(4)A 250Vac – CH150-16 versionVoltage-free switching contact. Power supply with two 1,5 V AA alkaline batteries. Batteries operation life more than 1 year. Low batteries charge indication