DC 4V-28V 0.28 Inch Mini LED Dual Display Digital Temperature Sensor with NTC Waterproof Metal Dual Probe Temperature Tester Specifications: Size: 45MM * 26MM Refresh rate: about 1S / times Supply voltage: DC 4-28V Accuracy: 1 C Measuring temperature: -20 C ~ 100 C Working temperature: -40 C to 80 C Sensor Type: 1M NTC waterproof metal probe Display: 0.28 LED Minimum resolution: 0.1 C Instructions 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 Cor above 100 C, digital also shows "- - -." [3] Acquisition normal temperature range: -20 C to 100 C, resolution 0.1 C, accuracy of 1 C. Product Usage: (1) measuring the temperature inside and outside the car (2) measuring the temperature inside and outside the air-conditioned room (3) measuring the temperature inside and outside the refrigerator (4) temperature measurement pond (5) baby bath water temperature measurement Package Included: 1 * Dual Display DC4-28V Thermometer NTC Metal Probe Temperature Sensor