Product Material: Electronic material Size: 38mm(length)*22mm(width)*14mm(height) Working voltage: 3.3--5.5V Clock chip: high-precision clock chip DS3231 Clock accuracy: within the range of 0-40, accuracy is 2ppm, and the annual error is about 1 minute With 2 calendar alarm clocks Programmable square wave output The real-time clock generates seconds, minutes, hours, day of the week, date, month and year, and provides leap year compensation with a validity period up to 2100 Built-in temperature sensor inside the chip, with an accuracy of 3 Memory chip: AT24C32 (storage capacity 32K) IIC bus interface, the maximum transmission speed is 400KHz (when the working voltage is 5V) Other IIC devices can be cascaded, the 24C32 address can be modified by short-circuiting A0/A1/A2, the default address is 0x57 With CR2032 battery Wiring instructions (take Arduino uno r3 as an example): SCLA5 SDAA4 VCC5V GNDGND Packing method: single anti-static packaging Quantity: 3 piece set Package content: 3*3 piece set of IIC module 1.Real Time Clock ChipThe DS3231 AT24C32 is used as a real time clock chip which keeps the time running even if the main power supply is off (with the help of a battery). 2.Complete Clock CalendarFunctionality Including Seconds, Minutes, Hours, Day, Date, Month, and Year, with Leap-Year Compensation Up to Year 2100. 3.Extremely AccurateDS3231 memory chips - AT24C32 ,extremely accurate I2C real-time clock (RTC), with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. 4.Two programmProvides programmable time-of day alarms and a calendar can be set to a square wave output. Address and data are transferred serially through an I2C bidirectional bus. 5.Safe EnoughA precision temperature-compensated voltage reference and comparator circuit monitors the status of VCC to detect power failures, provide a reset output. In addition, RST pin is monitored as generating a P reset.