Instructions for useFirst press the PWR button on the aquarium thermometer, and then put the sensor probe into the water. The included suction cups can attach the LCD screen to the side of the aquarium. Easy to ReadThe LCD display of the aquarium thermometer allows you to easily read the water temperature. The temperature unit can be toggled between C and F via a button. [Measurement Range] Aquarium thermometer measuring range is -50C to +70C / -58F to +158F, accuracy is +/-1C Dimensions: 5838.15mm Power supply: LR44 battery ( included). Wide UseThlevel Aquarium Thermometer is suitable for aquarium, aquarium, reptile aquarium, incubator, refrigerator, cigar, etc. It protects reptiles, fish and animals. Small animals are protected from dangerous temperatures. [Package Included] You will receive 2 threvel aquarium thermometers, each with 1 lr44, 1.5v coin cell battery and 2 suction cups. Probe cable length: 1 meter. Note: Do not put the thermometer in water, only the probe sensor is waterproof. ""