Adafruit PiRTC - Precise DS3231 Real Time Clock for Raspberry Pi

Key Features: Best battery-backed RTC you can get that allows your Raspberry Pi project to keep track of time if the power is lost Perfect for data-logging, clock-building, NTP servers, time-stamping, timers and alarms 100% genuine Maxim DS3231 board Works perfectly with any Raspberry Pi (Pi 1, Pi 2, Pi 3, Pi 4, Pi Zero, A+, B+ etc.) This is the best battery-backed real time clock (RTC) you can get that allows your Raspberry Pi project to keep track of time if the 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. This Real Time Clock (RTC) is the most precise you can get in a small, low power package.Most RTCs use an external 32kHz timing crystal that is used to keep time with low current draw. And that's all well and good, but those crystals have slight drift, particularly when the temperature changes (the temperature change