This is a great battery-backed real time clock (RTC) that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. Perfect for data-logging, clock-building, time stamping, timers, and alarms, etc. Equipped with PCF8523 RTC - it can run from 3.3V or 5V power & logic! Note: This product does not come with a CR1220 coin cell battery Comes as a fully assembled and tested breakout plus a small piece of header. You can solder header in to plug it into a breadboard, or solder wires directly.

Will keep time for 5 years or more. Two mounting holes. Plugs into any breadboard, or you can use wires. PCB & header are included.