DS3231 RTC Module
The DS3231 RTC is a low cost, battery backup, Real Time Clock, that connects to an I2C bus, providing accurate time information.
Many DS3231 modules, like this one, https://www.ebay.com/itm/314250880191, have two I2C devices on-board, a DS3231 RTC and a AT24C32 EEPROM, allowing the storage of information into non-volatile memory.