Zacro LCD Digital Aquarium Thermometer Fish Tank Water Terrarium Temperature Submerge probe into fish tank to measure water temperature (Submerge probe only, do not submerge thermometer in water). Easy to apply suction cup and easy to read lcd screen; temperature readings to within 1 degree Large, easy to read lcd display; compact design for discrete use Temperature range -50 degree Celsius ~ + 70 degree Celsius; Operating temperature -10 degree Celsius ~ +50 degree Celsius. Powered by one lr44 button cell (included)