10pcs RobotDyn RTC Real Time Clock DS1307 Module Board With I2C Bus Interface For Arduino
This is a real time clock (RTC) based on IC DS1307 that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost.
Use for data-logging, clock, timers and alarms.
The DS1307 can be easily connected to the Arduino, with I2C bus interface.
10 x Real Time Clock Module with battery