Usage Steps First press the PWR button of the aquarium thermometer; then put the sensor probe into the water; the attached suction cup can stick the LCD screen to the side of the aquarium. Easy to Read You can easily read the water temperature through the LCD screen of the aquarium thermometer. The temperature unit can be switched between C and F with the button. Measuring Range The measuring range of the aquarium thermometer is -50°C ~ +70°C / -58°F ~ 158°F, accuracy is ±1 degree Celsius. Dimensions: 58 x 38 x 15mm. Power supply: LR44 battery (included). Wide Application The aquarium thermometer is suitable for aquariums, reptile enclosures, incubators, refrigerators, and similar environments. It can help protect reptiles, fish, and small animals from dangerous temperatures. NOTE: Do not put the thermometer in water; only the probe sensor is waterproof.