This is the best battery-backed real-time clock (RTC) you can get that allows your Raspberry Pi project to record the time when power is lost. Perfect for data logging, clock building, NTP servers, time stamping, timers, and alarms, etc. Equipped with a genuine DS3231 RTC, it works great with the Raspberry Pi and has native kernel support. Works perfectly with any Raspberry Pi (or similar single-board Linux computer) including the Pi 1, Pi 2, Pi 3, Pi Zero, A , B , etc. Note: This product does not come with a CR1220 button cell battery. Feature Working voltage: 3.3V Product Dimensions: 22mm * 24mm Will keep time for 5 years or more IIC Addresses: 0X68
