Seeed Studio High Accuracy Pi RTC Add On Board with DS3231 for Raspberry Pi

Support Raspberry Pi 2/ 3 B/B+ Zero/4
Support seconds,minutes,hours,day of week,month, year
Support 24-hour or 12-hour format with AM/PM indicator
Low-Power Consumption
Two Time-of-Day Alarms
Fast (400kHz) I2C Interface
Typical Applications
Any applications need Real Time on Raspberry.