SpecificationMeasuring Range: -50°C to +70°C (-58°F to +158°F)Working Temperature: -10°C to +70°C (-50°F to +140°F )Maximum Precision: 0.1°CMargin of Error: +/- 1°CBattery: LR44 button battery (included)Sensor probe cable length: Approx. 3 feet (1 meter)Operation:1. Attach the display unit to the outside of the tank using the suction cups and submerge the probe into the water in the tank.2. Press and hold the power (PWR) button to turn on. Hold the power button for 3 seconds to turn off.Package include:1 x Fish Tank thermometers