Display Color: red Display Way: 0.28 inch LED digital tube Display: Digital Refresh Rate: 4s/times Measurement Precision: 1 celsius Operating Temperature: -40~85 celsius Shell Size: 47.8 x 28.8 x 15mm Sensor Type: NTC metal waterproof probe Power Supply Voltage: DC 4-28V Minimum Resolution: 0.1 celsius Measurement Temperature: -20~100 celsius Color: Black Material: ABS nstructions for use: [1] DC power supply: This product requires access 4-28V DC power supply, the red line for positive power supply, the black wire to the negative power. The greatest feature of this product: its own reverse anti-burning circuit, avoiding the user process due to improper operation problems. Friendly reminder: must not be connected with AC 220V Oh! [2] Display Description: When the temperature sensor is removed when the digital display "- - -", the temperature is below -20 Celsius or above 100 Celsius , digital also shows "- - -." [3] Acquisition normal temperature range: -20 Celsius to 100 Celsius , resolution 0.1 Celsius , accuracy of 1 Celsius . Product Usage: measuring the temperature inside and outside the car measuring the temperature inside and outside the air-conditioned room measuring the temperature inside and outside the refrigerator temperature measurement pond baby bath water temperature measurement Package contents: 2x monitor 4x 1M NTC waterproof metal probe 2x Wiring Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.