DS3231 Real Time Clock Module 3.3V/5V with Battery for Raspberry Pi

Module itself can adapt to 3.3V and 5V system without level conversion, this is a super easy!
two. Characteristics:
- -40 [deg.] C to + 85 C temperature range, timing accuracy is maintained at 5ppm ( 0.432 s / day)
- Continuous Timekeeping Battery Backup
- Low power consumption
- The device package and function DS3231 is compatible with
- complete calendar clock functions include seconds, minutes, hours, day, date, month and year time, and provide valid until 2100 leap Year compensation
- the two-day alarms
- 1Hz and 32.768kHz output
- reset output and buttons to input jitter
- High-speed (400kHz) I2C serial bus
- + 2.3V to + 5.5V supply voltage
- the accuracy of 3 C digital temperature sensor
- -40 C to + 85 C working temperature range
- 16 pin SO (300mil) package