WINGONEER Tiny RTC I2C DS1307 AT24C32 Real Time Clock Module For Arduino AVR PIC 51 ARM DS1307 I2C real-time clock chip (RTC) 24C32 32K I2C EEPROM memory. The module comes fully assembled. CR2032 Battery include Designed for Arduino tiny RTC. Arduino-compatible; Note: This is not original Arduino product.it is only a substitute accessories from WINGONEER