Features: The module is a low cost, high precision I2C real time clock (RTC) with integrated temperature compensated crystal oscillator (TCXO) and crystal. The device includes a battery input port that maintains accurate timing when the mains supply is disconnected. Integrated crystal oscillator improves long-term accuracy of the device. Both commercial and industrial temperature ranges are being provide, adopting a 16-pin 300 mil SO package. This product is made of high quality ABS material, strong and durable. This clock module also has other functions that extend the additional features and options range of the system host. Specification: Material: ABS Size: Approx. 3.8x2.2x1.2cm/1.50x0.87x0.47inch Working Voltage: 3.3-5.5V Clock Chip: High precision clock chip Clock Accuracy: Under 0-40¡æ accuracy 2ppm, annual error of about 1 minute With 2 calendar alarm clocks Programmable square wave output The real-time clock generates seconds, minutes, hours, weeks, dates, months, and years, and provides leap year compensation that is valid until 2100 The chip has its own temperature sensor with an accuracy of ¡À3¡æ Memory Chip: AT24C32 (storage capacity 32K) IIC Bus Interface: Transmission speed 400KHz (when the working voltage is 5V) Battery: CR2032 (included) Package List: 1 x Module