SainSmart Tiny RTC I2C DS1307 AT24C32 24C32 memory Real Time Clock Module for Arduino 24C32 32K I2C EEPROM memory. DS1307 based RTC with CR2032 battery (Battery included). Fully charged, it can provide the DS1307 timing 1. Compact design, 27mm * 28mm * 8.4mm. Leads to the a DS1307 clock pin, to provide the clock signal for the microcontroller.