Instructions for use: [1] For DC power supply: This product requires a 4-28V DC power supply. The red wire is the positive power lead, and the black wire is the negative power lead. A key feature of this product is its built-in reverse polarity protection circuit, which helps prevent damage from incorrect wiring. Friendly reminder: Do not connect to AC 220V. [2] Display: When the temperature sensor is disconnected, the digital display shows "- - -". The display also shows "- - -" when the temperature is below -20C or above 100C. [3] Measurement range: Normal operating range is -20C to 100C, with 0.1C resolution and 1C accuracy. Product Usage: (1) Measuring indoor and outdoor car temperature (2) Measuring indoor and outdoor room temperature (3) Measuring refrigerator internal and external temperature (4) Pond water temperature measurement (5) Baby bath water temperature measurement Specifications: Supply voltage: DC 4-28V Refresh rate: Approximately 1 second per reading Accuracy: 1C Temperature measurement range: -20C to 100C Operating temperature range: -40C to 80C Display color: Red and Green Sensor type: 1M NTC waterproof metal probe Display: 0.28 inch LED Resolution: 0.1C Dimensions: 48 x 29 x 18mm / 1.89 x 1.14 x 0.71 inches Quantity: 1 set Note: Please allow 1-3mm error due to manual measurement. Ensure you are comfortable with this before purchasing. Due to differences in monitor displays, the image may not reflect the actual color of the item. Thank you. No retail packaging Package Includes: 1 x Digital Thermometer 2 x Waterproof Metal Probes 1 x Power Supply Cable