Features: Brand new and high quality Time expansion board specially designed for RPi, with high-precision DS3231 Time clock chip on board, I2C communication, supporting external connection of more sensors. Suitable for RPi series motherboards with high-precision DS3231 Time clock chip and spare battery holder. It can time the year, month, week, day, hour, minutes and second, and the annual count can reach 2100 years You can choose 24-hour system or 12-hour system (AM/PM format). Two programmable alarm clocks. Provide complete supporting manuals (sample programs such as RPi C/C++ and MicroPython). Specifications: Material:Metal Type:With Battery/Without Batteries Working voltage: 3.3V Backup power supply voltage: 2.3V-5.5V Operating temperature:-40-85℃ Power consumption: 100nA (data and clock information are kept) Size:Approx.48.26x21mm/1.9x0.82inch Package Includes: 1x Time Module note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.